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Working Group on Seabird Ecology (WGSE). ICES CM 2004/C:05 ...

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<strong>ICES</strong> Oceanography Committee<br />

<strong>ICES</strong> <strong>CM</strong> <strong>2004</strong>/C:<strong>05</strong> Ref. A<strong>CM</strong>E, ACE<br />

Report of the<br />

<str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong> (<strong>WGSE</strong>)<br />

29 March–2 April <strong>2004</strong><br />

Aberdeen, UK<br />

This report is not to be quoted without prior c<strong>on</strong>sultati<strong>on</strong> with the General Secretary. The document is a report of an<br />

Expert <str<strong>on</strong>g>Group</str<strong>on</strong>g> under the auspices of the Internati<strong>on</strong>al Council for the Explorati<strong>on</strong> of the Sea and does not necessarily<br />

represent the views of the Council.


Internati<strong>on</strong>al Council for the Explorati<strong>on</strong> of the Sea<br />

C<strong>on</strong>seil Internati<strong>on</strong>al pour l’Explorati<strong>on</strong> de la Mer<br />

Palægade 2–4 DK–1261 Copenhagen K Denmark<br />

Teleph<strong>on</strong>e + 45 33 38 67 00 · Telefax +45 33 93 42 15<br />

www.ices.dk · info@ices.dk


C<strong>on</strong>tents<br />

1 Introducti<strong>on</strong>................................................................................................................................................................ 5<br />

1.1 Participati<strong>on</strong> .................................................................................................................................................... 5<br />

1.2 Terms of Reference......................................................................................................................................... 5<br />

1.3 Overview by the Chair .................................................................................................................................... 5<br />

1.4 Note <strong>on</strong> bird names ......................................................................................................................................... 6<br />

1.5 Acknowledgements......................................................................................................................................... 6<br />

2 Factors influencing trends in abundance of seabirds in the Baltic Sea....................................................................... 6<br />

2.1 Introducti<strong>on</strong>..................................................................................................................................................... 6<br />

2.2 Factors known or assumed to be resp<strong>on</strong>sible for the trends observed............................................................. 6<br />

2.2.1 Climate ............................................................................................................................................... 6<br />

2.2.2 Bycatch in fishing gear ........................................................................................................................ 6<br />

2.2.3 Fishery discards and offal.................................................................................................................... 7<br />

2.2.4 Oil polluti<strong>on</strong>......................................................................................................................................... 7<br />

2.2.5 Predati<strong>on</strong> by native and introduced predators...................................................................................... 7<br />

2.2.6 Coastal z<strong>on</strong>e development ................................................................................................................... 8<br />

2.2.7 Marine wind farms............................................................................................................................... 8<br />

2.2.8 Sand and gravel extracti<strong>on</strong>................................................................................................................... 8<br />

2.2.9 Hunting ............................................................................................................................................... 8<br />

2.2.10 Other factors ........................................................................................................................................ 8<br />

2.3 Discussi<strong>on</strong>....................................................................................................................................................... 9<br />

2.4 References....................................................................................................................................................... 9<br />

3 Progress in measuring impacts of at-sea wind farms <strong>on</strong> seabirds............................................................................. 10<br />

3.1 Introducti<strong>on</strong>................................................................................................................................................... 10<br />

3.2 Recent advances in measuring impacts of existing wind farms <strong>on</strong> seabird................................................... 10<br />

3.3 Recent progress in understanding bird migrati<strong>on</strong> at sea................................................................................ 10<br />

3.4 Recent progress in site-selecti<strong>on</strong> procedures ................................................................................................ 11<br />

3.5 Progress and future plans of m<strong>on</strong>itoring possible impacts of wind farms <strong>on</strong> seabirds.................................. 11<br />

3.6 References..................................................................................................................................................... 12<br />

4 Climatic effects <strong>on</strong> seabird populati<strong>on</strong> performance................................................................................................ 14<br />

4.1 Introducti<strong>on</strong>................................................................................................................................................... 14<br />

4.2 Relati<strong>on</strong>s between seabird populati<strong>on</strong> performance and climate .................................................................. 15<br />

4.2.1 Phenology .......................................................................................................................................... 15<br />

4.2.2 Breeding success................................................................................................................................ 16<br />

4.2.3 Survival ............................................................................................................................................. 16<br />

4.3 Scale issues ................................................................................................................................................... 16<br />

4.4 C<strong>on</strong>clusi<strong>on</strong>s................................................................................................................................................... 16<br />

4.5 Summary....................................................................................................................................................... 17<br />

4.6 References..................................................................................................................................................... 17<br />

5 A comparis<strong>on</strong> of seabird communities and prey c<strong>on</strong>sumpti<strong>on</strong> in the east and west north atlantic........................... 18<br />

5.1 Introducti<strong>on</strong>................................................................................................................................................... 18<br />

5.1.1 Populati<strong>on</strong> estimates .......................................................................................................................... 18<br />

5.2 Results........................................................................................................................................................... 20<br />

5.2.1 Breeding populati<strong>on</strong>s (adapted from <strong>ICES</strong> 2003).............................................................................. 20<br />

5.2.2 Seas<strong>on</strong>al changes in numbers and biomass of seabirds in <strong>ICES</strong> and NAFO areas ............................ 22<br />

5.2.3 C<strong>on</strong>sumpti<strong>on</strong> estimates...................................................................................................................... 24<br />

5.2.4 Comparis<strong>on</strong> to earlier models............................................................................................................ 25<br />

5.3 References..................................................................................................................................................... 26<br />

6 C<strong>on</strong>sumpti<strong>on</strong> of prey by seabirds in the North Sea as input for the Study <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> Multispecies Assessments in<br />

the North Sea (SGMSNS) ........................................................................................................................................ 29<br />

7 Ecological quality objectives.................................................................................................................................... 29<br />

7.1 Introducti<strong>on</strong>................................................................................................................................................... 29<br />

7.2 Proporti<strong>on</strong> of oiled comm<strong>on</strong> guillemots am<strong>on</strong>g those found dead or dying <strong>on</strong> beaches............................... 30<br />

7.3 Mercury c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs (and feathers)................................................................................. 31<br />

7.4 Organochlorine c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs ............................................................................................ 31<br />

7.5 Plastic particles in stomachs of seabirds ....................................................................................................... 32<br />

7.6 Local sandeel availability to black-legged kittiwakes................................................................................... 33<br />

7.6.1 Objective............................................................................................................................................ 33<br />

7.6.2 Can black-legged kittiwake breeding success be m<strong>on</strong>itored accurately?........................................... 33<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 3


7.6.3 Does black-legged kittiwake breeding success correlate with sandeel abundance? .......................... 34<br />

7.6.4 Are human impacts important?.......................................................................................................... 36<br />

7.6.5 Can a clearly defined objective be set?.............................................................................................. 36<br />

7.6.6 Can this EcoQ apply to much of the North Sea? ............................................................................... 36<br />

7.7 <strong>Seabird</strong> populati<strong>on</strong> trends as an index of seabird community health ............................................................ 37<br />

7.8 References..................................................................................................................................................... 37<br />

8 Summary of the size, distributi<strong>on</strong>, and status of seabird populati<strong>on</strong>s in the North Sea for the period 2000–<strong>2004</strong>,<br />

and any trends over recent decades in these populati<strong>on</strong>s, for input to REGNS in 2006........................................... 38<br />

8.1 Introducti<strong>on</strong>................................................................................................................................................... 38<br />

8.2 Populati<strong>on</strong> distributi<strong>on</strong> and size.................................................................................................................... 38<br />

8.2.1 UK (<strong>ICES</strong> IVa-c) ............................................................................................................................... 39<br />

8.2.2 Netherlands (<strong>ICES</strong> IVc)..................................................................................................................... 39<br />

8.2.3 Norway (<strong>ICES</strong> IVa and IIIa).............................................................................................................. 39<br />

8.2.4 Sweden (<strong>ICES</strong> IIIa)............................................................................................................................ 39<br />

8.2.5 Belgium (<strong>ICES</strong> IVc) .......................................................................................................................... 39<br />

8.2.6 Denmark (<strong>ICES</strong> IVb and IIIa) ........................................................................................................... 39<br />

8.2.7 Germany (<strong>ICES</strong> IVb)......................................................................................................................... 39<br />

8.3 Populati<strong>on</strong> trends .......................................................................................................................................... 39<br />

8.4 Future development of this term of reference ............................................................................................... 46<br />

8.5 Additi<strong>on</strong>al references .................................................................................................................................... 46<br />

9 Recommendati<strong>on</strong>s.................................................................................................................................................... 47<br />

9.1 Chair of <strong>WGSE</strong>............................................................................................................................................. 47<br />

9.2 Proposal for next meeting ............................................................................................................................. 47<br />

10 Annexes.................................................................................................................................................................... 49<br />

Annex 1 List of participants ............................................................................................................................. 49<br />

Annex 2 Terms of Reference............................................................................................................................ 50<br />

Annex 3 English and scientific names of birds menti<strong>on</strong>ed in this report ......................................................... 52<br />

4<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


1 INTRODUCTION<br />

1.1 Participati<strong>on</strong><br />

The meeting participants are listed in Annex 1.<br />

1.2 Terms of Reference<br />

The Terms of Reference for the <strong>2004</strong> meeting of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong> (<strong>WGSE</strong>) are given in<br />

C.Res.2003/2C<strong>05</strong>. This resoluti<strong>on</strong> is in Annex 2.<br />

1.3 Overview by the Chair<br />

The <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> met for five days (29 March to 2 April <strong>2004</strong>), and was attended by twelve nominated<br />

representatives from seven countries (Annex 1). It was able to address all terms of reference, though in varying detail,<br />

and the results are reported here.<br />

We reviewed factors influencing trends in abundance of seabirds in the Baltic Sea. This review followed from our<br />

review of the status and trends of Baltic Sea birds carried out in 2003. Although our group lacked representatives from<br />

many Baltic countries, and so was unable to make detailed evaluati<strong>on</strong> of local literature and knowledge, the review<br />

clearly shows that many human impacts affect Baltic seabirds, including fishery bycatch, provisi<strong>on</strong> of discards, habitat<br />

change and increases in numbers of predators <strong>on</strong> ground-nesting birds. Increasing rates of oil tanker traffic represent a<br />

potential hazard in the immediate future.<br />

We briefly reviewed progress over the last twelve m<strong>on</strong>ths in the study of seabirds in relati<strong>on</strong> to marine wind farms.<br />

Although several marine wind farms are now commissi<strong>on</strong>ed, there are still no established means to assess the numbers<br />

of bird collisi<strong>on</strong>s. Methods to assess this are still at a developmental stage, but advances have been made in assessing<br />

the relative suitability of sites that could be developed as wind farms in relati<strong>on</strong> to their importance for seabirds.<br />

We reviewed effects of climate <strong>on</strong> seabird populati<strong>on</strong> performance, a topic that has received much increased research<br />

attenti<strong>on</strong> recently and <strong>on</strong>e where l<strong>on</strong>g term data sets <strong>on</strong> seabird ecology provide excellent opportunities to investigate<br />

relati<strong>on</strong>ships with food supply and with envir<strong>on</strong>mental factors such as oceanography and climate. While the presence of<br />

many effects of climate can be established, further work to assess the relative importance of climate and other factors,<br />

such as predators or fisheries, remains to be undertaken, perhaps focusing <strong>on</strong> specific situati<strong>on</strong>s where detailed data<br />

exist such as in parts of the North Sea.<br />

A l<strong>on</strong>gstanding investigati<strong>on</strong> into the energy c<strong>on</strong>sumpti<strong>on</strong> by seabirds in the <strong>ICES</strong> and NAFO Regi<strong>on</strong>s was brought to a<br />

stage where we present total biomass and energy c<strong>on</strong>sumpti<strong>on</strong> estimates for each seas<strong>on</strong> of the year. A striking feature<br />

c<strong>on</strong>trasting between the regi<strong>on</strong>s is the higher proporti<strong>on</strong> of small seabirds in the NAFO Regi<strong>on</strong>, higher c<strong>on</strong>sumpti<strong>on</strong><br />

from a lower trophic level than occupied by seabirds in the <strong>ICES</strong> Regi<strong>on</strong>, and the relatively greater importance of l<strong>on</strong>gdistance<br />

migrant seabirds taking resources from the NAFO Regi<strong>on</strong>. These patterns deserve further investigati<strong>on</strong> in<br />

relati<strong>on</strong> to foodweb structure in the two regi<strong>on</strong>s.<br />

Our Term of Reference f) required <strong>WGSE</strong> to prepare data <strong>on</strong> the c<strong>on</strong>sumpti<strong>on</strong> of different prey by seabirds in the North<br />

Sea, in a format specified by SGMSNS. <strong>WGSE</strong> received <strong>on</strong>ly very brief guidance from SGMSNS <strong>on</strong> the format<br />

required, via a member of <strong>WGSE</strong> who had already attended WGMME and obtained some details there. However, he<br />

pointed out that WGMME had not worked <strong>on</strong> this ToR as it was unclear what was needed, and it appeared that this<br />

work was now being taken forward by an EC c<strong>on</strong>tract ‘BECAUSE’ rather than through <strong>ICES</strong>. <strong>WGSE</strong> would be happy<br />

to work <strong>on</strong> this ToR intersessi<strong>on</strong>ally in future if <strong>ICES</strong> wishes to c<strong>on</strong>tinue with this work.<br />

A major part of this year’s <strong>WGSE</strong> work was discussi<strong>on</strong> of the six EcoQOs that involve seabird ecology. Five of these<br />

utilize seabirds to assess the status of other topics (oil, plastic, mercury, organochlorines, sandeels) and <strong>on</strong>ly <strong>on</strong>e focuses<br />

<strong>on</strong> seabird populati<strong>on</strong>s themselves. <strong>WGSE</strong> made good progress with all of these EcoQOs except the <strong>on</strong>e focused <strong>on</strong><br />

seabird populati<strong>on</strong>s, where there is a need for more c<strong>on</strong>siderati<strong>on</strong> of metrics and objectives.<br />

Term of Reference h) was to start to prepare for input of data <strong>on</strong> seabird populati<strong>on</strong>s to REGNS in 2006. This topic was<br />

warmly received by <strong>WGSE</strong>, who felt that such an approach was very much in line with our own thinking and was<br />

highly desirable. So we have begun this process with enthusiasm. Although compiling appropriate data sets may require<br />

c<strong>on</strong>siderable effort intersessi<strong>on</strong>ally, we have started by providing an outline of the sorts of time-series of seabird data<br />

that are available and that we think would be useful in the approach we envisage being taken by REGNS.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 5


Our <strong>2004</strong> meeting attracted twelve <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> members. The c<strong>on</strong>siderable efforts have been rewarded by a sense<br />

of achievement and new understandings from the data brought together, and also of the great benefits and synergies of<br />

group working to clear objectives.<br />

Following the new ‘sandwich’ arrangement, <strong>WGSE</strong> offered stakeholders the possibility to join us before and after the<br />

<str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> meeting. We were joined by Dr Euan Dunn, of the Royal Society for the Protecti<strong>on</strong> of Birds (RSPB)/<br />

Birdlife Internati<strong>on</strong>al, <strong>on</strong> Friday afterno<strong>on</strong> and we discussed the c<strong>on</strong>tents of the nearly completed <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g><br />

Report and the proposed Terms of Reference for <strong>WGSE</strong> 20<strong>05</strong>. We note the relative impracticality for representatives of<br />

organisati<strong>on</strong>s located at distance from the meeting venue to be able to discuss issues both before and after meetings.<br />

Also the ‘sandwich’ approach was announced <strong>on</strong>ly shortly before our meeting so that interested parties would have had<br />

little time to arrange to attend. However, <strong>WGSE</strong> welcomes participati<strong>on</strong> in this form and is pleased to receive scientific<br />

informati<strong>on</strong> from any source.<br />

1.4 Note <strong>on</strong> bird names<br />

Throughout the text we provide the comm<strong>on</strong> English names of bird species. A full list of species names together with<br />

their scientific binomial appears in Annex 3.<br />

1.5 Acknowledgements<br />

The <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> wishes to thank the Fishery Research Service, Aberdeen, for providing a room for our meeting, and<br />

keeping the coffee machine topped up. We particularly thank Sim<strong>on</strong> Greenstreet, Ray Johnst<strong>on</strong>e and Dick Ferro for<br />

providing facilities, T<strong>on</strong>y Fox, Sim<strong>on</strong> Greenstreet, Ommo Hüppop, Bill M<strong>on</strong>tevecchi and Dick Veit for providing<br />

informati<strong>on</strong> and reviewing c<strong>on</strong>tent of secti<strong>on</strong>s of the report, and Bill Turrell for joining us for a very useful discussi<strong>on</strong><br />

of the approach being developed in REGNS.<br />

2 FACTORS INFLUENCING TRENDS IN ABUNDANCE OF SEABIRDS IN THE BALTIC SEA<br />

Term of Reference: Review the factors influencing trends in abundance of seabirds in the Baltic Sea.<br />

2.1 Introducti<strong>on</strong><br />

The status and trends of seabirds in the Baltic Sea have been reviewed at the 2003 meeting of <strong>WGSE</strong> (<strong>ICES</strong>, 2003).<br />

Given that there have been major declines in numbers of certain populati<strong>on</strong>s and species and increases in numbers in a<br />

few species, it is important to review likely causes for these trends. Because of a bulk of local literature in different<br />

languages in all countries bordering the Baltic Sea and also a substantial amount of unpublished informati<strong>on</strong> it is quite<br />

difficult to get a good country-wide coverage of these factors. The presence at <strong>WGSE</strong> of representatives from countries<br />

bordering the Baltic Sea needs to be higher to fill these apparent gaps in detail. This secti<strong>on</strong> is thus to specify some of<br />

the main factors known to influence seabird populati<strong>on</strong> trends in the Baltic Sea without being necessarily<br />

comprehensive. Also, many more details will be summarised later by others in a report to be produced for HELCOM.<br />

2.2 Factors known or assumed to be resp<strong>on</strong>sible for the trends observed<br />

2.2.1 Climate<br />

Winters of different strength have a substantial influence <strong>on</strong> distributi<strong>on</strong>s and numbers of waterbirds al<strong>on</strong>g the coast but<br />

also in offshore areas (e.g., Kube 1996; Vaitkus 2001; Garthe et al. 2003). Species with relatively restricted habitat<br />

selecti<strong>on</strong>, especially those living in shallow waters (e.g., comm<strong>on</strong> goldeneye and Steller's eider), resp<strong>on</strong>d to cold<br />

winters and thus ice formati<strong>on</strong> much more quickly than species exhibiting a more flexible habitat selecti<strong>on</strong> such as<br />

velvet scoter and l<strong>on</strong>g-tailed ducks (Zydelis, 2001). The climatic trend is thus of major importance for explaining trends<br />

in birds spending their winter in the Baltic Sea, with many species and substantial proporti<strong>on</strong>s leaving the eastern Baltic<br />

already in normal winters and many more leaving even the generally warmer southern and western parts in cold winters.<br />

Unfortunately, hardly any large-scale surveys have been c<strong>on</strong>ducted in offshore areas in cold winters so far so that the<br />

extent of changes outside the coastal areas remains partly speculative.<br />

2.2.2 Bycatch in fishing gear<br />

The scale of additi<strong>on</strong>al mortality imposed up<strong>on</strong> different seabird populati<strong>on</strong>s from the use of different passive fishing<br />

gears throughout the Baltic Sea is currently unknown. It is known that bycatch of many species occurs throughout the<br />

6<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


egi<strong>on</strong>, but its size and importance has not been assessed. A number of nati<strong>on</strong>al or regi<strong>on</strong>al investigati<strong>on</strong>s has been<br />

undertaken, focusing <strong>on</strong> gill-net fisheries, e.g., in Finland (Hario 1998), Latvia (Urtans and Priednieks 2000), Lithuania<br />

(Dagys and Zydelis 2002), Poland (Stempniewicz, 1994), and Germany (Kirchhoff, 1982; Schirmeister, 2003). The<br />

numerical effects of such activities vary with the type of gears used and the temporal and spatial overlap between<br />

fishery activities and seabird distributi<strong>on</strong> and abundance. The impacts at the populati<strong>on</strong> level will vary according to the<br />

demographic patterns and the populati<strong>on</strong>s c<strong>on</strong>cerned: l<strong>on</strong>g-lived species with low reproductive rates suffer greater<br />

effects <strong>on</strong> overall abundance than short-lived species with high reproductive potential. A well-documented example is<br />

the study of comm<strong>on</strong> guillemots ringed in Sweden. Bycatches of this species appear to be the single most serious threat<br />

to the populati<strong>on</strong>, and the proporti<strong>on</strong> of recoveries of ringed birds in fishing gear, compared with other finding<br />

circumstances, has significantly increased during a 28-year period (Österblom et al., 2002). 50% of guillemots found<br />

dead were caught in fishing nets, most notably in drift gillnets for salm<strong>on</strong> and set gillnets for cod. Österblom et al.<br />

(2002) c<strong>on</strong>cluded that the observed increased use of cod gillnets in the Baltic Sea may have c<strong>on</strong>tributed to the observed<br />

decrease in guillemot adult survival rate.<br />

2.2.3 Fishery discards and offal<br />

Scavenging <strong>on</strong> discards and offal is a widespread phenomen<strong>on</strong> in the Baltic Sea as it is in other shelf areas of Europe,<br />

but the number of bird species involved is generally lower and str<strong>on</strong>gly biased towards gulls, especially herring gulls<br />

(Garthe and Scherp, 2003). Herring gulls were clearly the most numerous scavenging species in all areas and all seas<strong>on</strong>s<br />

studied, followed by great black-backed gulls, lesser black-backed gulls and mew gulls. High percentages of discarded<br />

gadids (cod, whiting), clupeids (herring, sprat), scad, rockling and offal were c<strong>on</strong>sumed by seabirds during experimental<br />

discarding <strong>on</strong> fishing boats, whereas percentages of flatfish c<strong>on</strong>sumed were extremely low. By combining official<br />

discard and offal statistics and experimental discarding, Garthe and Scherp (2003) estimated that 6,500 t of fish discards<br />

and 16,000 t of offal were c<strong>on</strong>sumed annually by seabirds in the Baltic Sea. The proporti<strong>on</strong> of discards in herring gull<br />

pellets was <strong>on</strong> average 1.6% (range: 0–4.5%) and 17.5% (range: 9.4–25.5%), respectively, at two study sites in the<br />

southwestern Baltic Sea. Even if these percentages are not extremely high it seems likely that herring gulls in particular<br />

but also great black-backed gulls in winter and lesser black-backed gulls in summer should have benefited from this<br />

surplus food.<br />

2.2.4 Oil polluti<strong>on</strong><br />

Zydelis and Dagys (1997) c<strong>on</strong>sider oil polluti<strong>on</strong> due to ship traffic as the most important threat to wintering seabirds<br />

and waterbirds in the coastal z<strong>on</strong>e of Lithuania. Oil rates of beached birds were up to 34% in years without any major<br />

accidents and up to 90% in years with such accidents. As oil explorati<strong>on</strong> is assumed to increase in the eastern Baltic Sea<br />

chr<strong>on</strong>ic oil polluti<strong>on</strong> is thought to be a major factor for the forthcoming years. Particular emphasis is put to str<strong>on</strong>gly<br />

increasing traffic of oil tankers transporting oil from the eastern Baltic Sea coast into the North Sea and NE Atlantic.<br />

Major accidents occur from time to time. In March 2001, 1,750 birds were found dead after the 'Baltic Carrier' oil spill<br />

with estimates up to ten times higher:<br />

(www.europa.eu.int/comm/envir<strong>on</strong>ment/civil/marin/reports_publicati<strong>on</strong>s/final_reports/baltic_carrier.pdf). In June<br />

2003, an oil spill from the “Fu Shan Hai” hit Christiansø, where 164 birds were found dead; total mortality was<br />

estimated as up to ten times higher, with about 50% being comm<strong>on</strong> guillemots (www.danbbs.dk/~lynx/chroe_obs/).<br />

2.2.5 Predati<strong>on</strong> by native and introduced predators<br />

Predati<strong>on</strong> by mammalian ground predators is <strong>on</strong>e of the main reas<strong>on</strong>s for declines in breeding gulls and terns (as well as<br />

shorebirds) al<strong>on</strong>g the Baltic Sea coasts. Different predators are involved, native (e.g., red fox Vulpes vulpes) as well as<br />

introduced (e.g., American mink Mustela vis<strong>on</strong>) species. In additi<strong>on</strong> to other local factors, predati<strong>on</strong> and disturbance by<br />

American minks has been <strong>on</strong>e the main factors resp<strong>on</strong>sible for the decline of black-headed gulls in Latvia (e.g., Viksne<br />

and Janaus, 1993; Viksne et al., 1996). Mew gulls in Schleswig-Holstein (northern Germany) suffer from repeated<br />

breeding failure due to intense predati<strong>on</strong> above all from red foxes (Kubetzki, 2001). Further east al<strong>on</strong>g the German<br />

Baltic Sea coast, foxes and some other mammals caused severe reducti<strong>on</strong> in breeding success and breeding populati<strong>on</strong>s<br />

of many coastal species (Dierschke et al., 1995; Hartmann and Stier, 2003).<br />

Large-scale losses of breeding habitats such as small islands which are hardly accessible to predators have str<strong>on</strong>gly<br />

enhanced the predati<strong>on</strong> pressure <strong>on</strong> the remaining breeding col<strong>on</strong>ies. These col<strong>on</strong>ies are usually easily accessible for<br />

predators (Kubetzki, 2001). After the experimental removal of minks from islands in SW Finland some species returned<br />

to their former breeding sites (Nordström et al., 2003). However, removal of native species is a much bigger issue at<br />

least for most of the southern Baltic Sea coast (Garthe et al., 2003).<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 7


2.2.6 Coastal z<strong>on</strong>e development<br />

Many coastal z<strong>on</strong>es of the Baltic Sea have been developed extensively so that most natural habitats have been<br />

destroyed. This is most obvious in countries where ec<strong>on</strong>omic development occurred earlier. Protected areas are often<br />

the <strong>on</strong>ly places where breeding seabirds and also coastal birds can still reproduce though indirect effects such as<br />

predati<strong>on</strong> pressure can be very intense. Herring gulls and mew gulls seem to circumvent the problem of lacking natural<br />

breeding habitats by founding new col<strong>on</strong>ies <strong>on</strong> buildings with flat-roofs, basically doing that in the much-exploited<br />

western part of Germany and hardly so in the less-exploited eastern part (Kubetzki, 2001; Garthe et al., 2003). Most<br />

other breeding species resp<strong>on</strong>d simply by decreasing in populati<strong>on</strong> sizes al<strong>on</strong>g with the disappearing breeding habitats.<br />

2.2.7 Marine wind farms<br />

This issue is reviewed in Secti<strong>on</strong> 3 of this WG report and also in the WG reports of 2002 and 2003 (<strong>ICES</strong>, 2002; 2003)<br />

so that informati<strong>on</strong> will not be reported here. However, as the first wind farms have just been set up, they cannot have<br />

been influenced the trends of seabirds in the Baltic Sea area.<br />

2.2.8 Sand and gravel extracti<strong>on</strong><br />

Sand and gravel extracti<strong>on</strong> is carried out at some locati<strong>on</strong>s in the Baltic Sea with plans for many more sites to be<br />

exploited. No informati<strong>on</strong> is available so far as how such activities may influence seabirds. However, there is at least<br />

some overlap between major sea duck (and other seabird) c<strong>on</strong>centrati<strong>on</strong>s and extracti<strong>on</strong> sites so that at least food<br />

availability for benthivorous seabirds might possibly be affected. The observed l<strong>on</strong>g-term trend for Baltic Sea seabirds<br />

is nevertheless unlikely to have been caused by the current level of sand and gravel extracti<strong>on</strong>.<br />

2.2.9 Hunting<br />

Hunting is still performed in Denmark at a large scale. The most recent figures for annual bags of sea ducks in Denmark<br />

are given by Clausager (2003); he estimated 86,400 comm<strong>on</strong> eiders in the seas<strong>on</strong> 2000/2001 and 77,400 in the seas<strong>on</strong><br />

2001/02, the values for other sea ducks are less high: comm<strong>on</strong> scoter 4,100 and 2,800, respectively, velvet scoter 2,800<br />

and 1,800, respectively, and l<strong>on</strong>g-tailed duck 4,700 and 1,600, respectively.<br />

2.2.10 Other factors<br />

Though generally difficult to show, there seems to be changes in fish availability affecting reproductive performance of<br />

comm<strong>on</strong> guillemots breeding at Stora Karlsö, Sweden. Chick fledging body mass has decreased over the period 1989–<br />

2000 as has the body c<strong>on</strong>diti<strong>on</strong> of sprats, their main food. The sprat populati<strong>on</strong> itself has changed c<strong>on</strong>siderably over the<br />

past decades due to changes in the Baltic Sea ecosystem (Österblom et al., 2001).<br />

Further effects are possibly due to eutrophicati<strong>on</strong>, litter and other polluti<strong>on</strong> although these are relatively rarely<br />

documented. In general, however, there is a slightly positive trend as polluti<strong>on</strong> seems to be reduced in the Baltic Sea<br />

(Rheinheimer, 1998). Organochlorine levels in comm<strong>on</strong> guillemots eggs from the Baltic have decreased c<strong>on</strong>siderably<br />

during the last decades (Bignert et al., 1995).<br />

Furthermore, disturbance by ship traffic and recreati<strong>on</strong>al activities play certainly a role, well-documented examples are<br />

rare though (e.g., Mikola et al., 1994). Protected areas turn into refugees if the surrounding areas are intensively<br />

exploited, e.g., by recreati<strong>on</strong>al boat traffic (Dierschke, 1998).<br />

Another aspect which has influenced those seabirds feeding <strong>on</strong> land is change in agricultural practice. Both the<br />

reducti<strong>on</strong> of meadows and the increased use of winter crops has reduced food availability for mew Gulls and blackheaded<br />

gulls breeding at or near the German Baltic Sea coast (Berndt, 1980; Kubetzki, 2001).<br />

Finally, it needs to be clearly stated that some of the reas<strong>on</strong>s for populati<strong>on</strong> changes have not been (fully) understood. A<br />

dramatic decline in the number of wintering eiders from ca. 800,000 to ca. 370,000 occurred in Danish waters between<br />

1990 and 2000 (Desholm et al., 2002). Given that Danish waters c<strong>on</strong>stitute the most important wintering area of eiders<br />

from the Baltic/Wadden Sea flyway, these reports str<strong>on</strong>gly suggest major declines have taken place in this populati<strong>on</strong><br />

over the last decade. There seems to be no comm<strong>on</strong> explanati<strong>on</strong> for the observed decline in the Baltic/Wadden Sea<br />

eiders. Local decreases in discrete breeding populati<strong>on</strong>s have been related to periods of very low duckling survival<br />

caused by viral infecti<strong>on</strong>s, mass adult mortality due to avian cholera and reduced adult annual survival rates. In<br />

8<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


additi<strong>on</strong>, mass mortality events <strong>on</strong> the wintering grounds have occurred in the Wadden Sea potentially affecting<br />

breeding populati<strong>on</strong>s throughout the range (Desholm et al., 2002).<br />

2.3 Discussi<strong>on</strong><br />

The Baltic Sea is str<strong>on</strong>gly influenced by human activities all around the coast, likely more than most other seas. This<br />

has led to a full range of different anthropogenic factors which affect breeding seabirds <strong>on</strong> land and at the coast as well<br />

as resting and wintering seabirds al<strong>on</strong>g the coast and further offshore. Many of these factors are inter-c<strong>on</strong>nected as has,<br />

e.g., been dem<strong>on</strong>strated for the decreases in mew gulls and black-headed gulls (see above).<br />

2.4 References<br />

Berndt, R.K. 1980. Bestand und Bestandsentwicklung v<strong>on</strong> Silber-, Sturm- und Lachmöwe (Larus argentatus, canus und<br />

ridibundus) in der Seenplatte des Östlichen Hügellandes (Schleswig-Holstein) 1970–1979. Corax 8: 131–149.<br />

Bignert, A., Litzen, K., Odsjö, T., Olss<strong>on</strong>, M., Perss<strong>on</strong>, W., and Reutergardh, L. 1995. Time related factors influence<br />

the c<strong>on</strong>centrati<strong>on</strong>s of DDT, PCBs and shell parameters in eggs of Baltic guillemots (Uria aalge), 1961–1989.<br />

Envir<strong>on</strong>mental Polluti<strong>on</strong>, 89: 27–36.<br />

Clausager, I. 2003. Vingeindsamling fra jagtsæs<strong>on</strong>en 2002/03 i Danmark. DMU rapport 452, 72 pp.<br />

Dagys, M., and Zydelis, R. 2002. Bird bycatch in fishing nets in Lithuanian coastal waters in wintering seas<strong>on</strong> 2001–<br />

2002. Acta Zoologica Lituanica, 12: 276–282.<br />

Desholm, M., Christensen, T.K., Scheiffarth, G., Hario, M., Anderss<strong>on</strong>, Å., Ens, B., Camphuysen, C.J., Nilss<strong>on</strong>, L.,<br />

Waltho, C.M., Lorentsen, S.-H., Kuresoo, A., Kats, R.K.H., Fleet, D.M., and Fox, A.D. 2002. Status of the<br />

Baltic/Wadden Sea populati<strong>on</strong> of the Comm<strong>on</strong> Eider Somateria m. mollissima. Wildfowl, 53: 167–203.<br />

Dierschke, V. 1998. Anthropogene und natürliche Störreize für Küstenvögel im Windwatt v<strong>on</strong> Hiddensee. Seevögel 19,<br />

S<strong>on</strong>derheft: 53–56.<br />

Dierschke, V., Helbig, A.J., and Barth, R. 1995. Ornithologischer Jahresbericht 1994 für Hiddensee und Umgebung.<br />

Berichte Vogelwarte Hiddensee, 12: 41–96.<br />

Garthe, S., and Scherp, B. 2003. Utilizati<strong>on</strong> of discards and offal from commercial fisheries by seabirds in the Baltic<br />

Sea. <strong>ICES</strong> Journal of Marine Science, 60: 980–989.<br />

Garthe, S., Ullrich, N., Weichler, T., Dierschke, V., Kubetzki, U., Kotzerka, J., Krüger, T., S<strong>on</strong>ntag, N., and Helbig,<br />

A.J. 2003. See- und Wasservögel der deutschen Ostsee - Verbreitung, Gefährdung und Schutz. Report to the<br />

Federal Agency for Nature C<strong>on</strong>servati<strong>on</strong>, B<strong>on</strong>n.<br />

Hario, M. 1998. Review of incidental catches of seabirds in fisheries in Finland. CAFF Technical Report 1: 20–24.<br />

Hartmann, E., and Stier, N. 2003. Raubsäuger in Küstenvogelschutzgebieten Mecklenburg-Vorpommerns – einer<br />

Gefahr für Bodenbrüter? Vogelkundliche Berichtung Niedersachsen, 35: 83–90.<br />

<strong>ICES</strong>. 2002. Report of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong>. <strong>ICES</strong> <strong>CM</strong> 2002/C:04.<br />

<strong>ICES</strong>. 2003. Report of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong>. <strong>ICES</strong> <strong>CM</strong> 2003/C:03.<br />

Kirchhoff, K. 1982. Wasservogelverluste durch die Fischerei an der schleswig-holsteinischen Ostseeküste. Vogelwelt,<br />

103: 81–89.<br />

Kube, J. 1996. The ecology of macrozoobenthos and seaducks in the Pomeranian Bay. Meereswissenschaftliche<br />

Berichte, 18: 1–128.<br />

Kubetzki, U. 2001. Zum Bestandsrückgang der Sturmmöwe (Larus canus) an der schleswig-holsteinischen Ostseeküste<br />

– Ausmaß, Ursachen und Schutzk<strong>on</strong>zepte. Corax, 18: 301–323.<br />

Mikola, J., Miettinen, M., Lehikoinen, E., and Lehtilae, K. 1994. The effects of disturbance caused by boating <strong>on</strong><br />

survival and behaviour of Velvet Scoter Melanitta fusca ducklings. Biological C<strong>on</strong>servati<strong>on</strong>, 67: 119–124.<br />

Nordström, M., Högmander, J., Laine, J., Nummelin, J., Laanetu, N., and Korpimäki, E. 2003. Effects of feral mink<br />

removal <strong>on</strong> seabirds, waders and passerines <strong>on</strong> small islands in the Baltic Sea. Biological C<strong>on</strong>servati<strong>on</strong>, 109: 359–<br />

368.<br />

Österblom, H., Bignert, A., Franss<strong>on</strong>, T., and Olss<strong>on</strong>, O. 2001. A decrease in fledging body mass in Comm<strong>on</strong> Guillemot<br />

Uria aalge chicks in the Baltic Sea. Marine <strong>Ecology</strong> Progress Series, 224: 3<strong>05</strong>–309.<br />

Österblom, H., Franss<strong>on</strong>, T., and Olss<strong>on</strong>, O. 2002. Bycatches of Comm<strong>on</strong> Guillemots (Uria aalge) in the Baltic Sea<br />

gillnet fishery. Biological C<strong>on</strong>servati<strong>on</strong> 1<strong>05</strong>: 309–319.<br />

Rheinheimer, G. 1998. Polluti<strong>on</strong> in the Baltic Sea. Naturwissenschaften, 85: 318–329.<br />

Schirmeister, B. 2003. Verluste v<strong>on</strong> Wasservögeln in Stellnetzen der Küstenfischerei – das Beispiel der Insel Usedom.<br />

Meer und Museum, 17: 160–166.<br />

Rheinheimer, G. 1998. Polluti<strong>on</strong> in the Baltic Sea. Naturwissenschaften, 85: 318–329.<br />

Stempniewicz, L. 1994. Marine birds drowning in fishing nets in the Gulf of Gdansk (southern Baltic): numbers,<br />

species compositi<strong>on</strong>, age and sex structure. Ornis Svecica, 4: 123–132.<br />

Urtans, E., and Priednieks, J. 2000. The present status of seabirds by-catch in Latvia coastal fishery of the Baltic Sea.<br />

<strong>ICES</strong> C.M. 2000/J:14.<br />

Vaitkus, G. 2001. Spatial dynamics of regi<strong>on</strong>al wintering populati<strong>on</strong>s of seabirds in the gradient of winter climatic<br />

c<strong>on</strong>diti<strong>on</strong>s. Acta Zoologica Lituanica, 11: 273–279.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 9


Viksne, J., and Janaus, M. 1993. What is going <strong>on</strong> with the Black-headed Gull (Larus ridibundus) at the eastern coast of<br />

the Baltic? Ring 15: 154–158.<br />

Viksne, J., Janaus, M., and Stipniece, A. 1996. Recent trends of the Black-headed Gull (Larus ridibundus L.) populati<strong>on</strong><br />

in Latvia. Ornis Svecica 6: 39–44.<br />

Zydelis, R. 2001. Some remarks <strong>on</strong> effect of climatic parameters <strong>on</strong> wintering waterbirds in the eastern Baltic. Acta<br />

Zoologica Lituanica 11: 303–308.<br />

Zydelis, R., and Dagys, M. 1997. Winter period ornithological impact assessment of oil related activities and sea<br />

transportati<strong>on</strong> in Lithuanian inshore waters of the Baltic Sea and in the Kursiu Lago<strong>on</strong>. Acta Zoologica Lituanica,<br />

Ornithologia, 6: 45–65.<br />

3 PROGRESS IN MEASURING IMPACTS OF AT-SEA WIND FARMS ON SEABIRDS<br />

Term of Reference: review progress in studies of seabirds in relati<strong>on</strong> to marine wind farms.<br />

3.1 Introducti<strong>on</strong><br />

During the last two years, the possible impacts of at-sea wind farms have been described in two relatively l<strong>on</strong>g secti<strong>on</strong>s<br />

by the <strong>ICES</strong> <strong>WGSE</strong> (<strong>ICES</strong>, 2002; 2003). This year, we c<strong>on</strong>centrate our efforts to report <strong>on</strong> progress obtained during the<br />

last 12 m<strong>on</strong>ths. The sub-secti<strong>on</strong>s of this report are structured accordingly. We furthermore expect major progress from<br />

<strong>on</strong>-going studies to be reported at a workshop to be held in Billund, Denmark, <strong>on</strong> 21–22 September <strong>2004</strong>, organised by<br />

Elsam Engineering, Energi E2, the Danish Forest and Nature Agency, and the Danish Energy Authority. Full details of<br />

the event can be found <strong>on</strong> the web-site http://www.hornsrev.dk/Engelsk/nyheder/c<strong>on</strong>ference_hornsrev.pdf.<br />

3.2 Recent advances in measuring impacts of existing wind farms <strong>on</strong> seabird<br />

There have been investigati<strong>on</strong>s into effects of wind farms <strong>on</strong> seabirds in the Danish wind farms at Horns Rev (North<br />

Sea) and Nysted (Baltic Sea) but up to date informati<strong>on</strong> could not be obtained to be included in this report.<br />

3.3 Recent progress in understanding bird migrati<strong>on</strong> at sea<br />

Informati<strong>on</strong> <strong>on</strong> the nature of bird migrati<strong>on</strong> at sea provides an important basis to predict collisi<strong>on</strong> risks and avoidance of<br />

sea areas where wind farms are installed. C<strong>on</strong>sequently in advance of the expected high numbers of wind farms built<br />

offshore the German coast, progress had been made in order to increase our knowledge of bird movements at sea in<br />

areas where wind farms are planned.<br />

Detailed results of recent investigati<strong>on</strong>s have been reviewed in our last report (<strong>ICES</strong>, 2003). Within the frame of<br />

ecological research <strong>on</strong> windfarms in Germany (project “BEOFINO”, 2002–<strong>2004</strong>), the Institute of Avian Research,<br />

Wilhelmshaven and Helgoland, is performing the sub-project “Effects <strong>on</strong> bird migrati<strong>on</strong>” (Hüppop and Exo, <strong>2004</strong>). In<br />

summer 2003 the research platform FINO-1 was erected 45 km north of Borkum. It is equipped with both a vertically<br />

and a horiz<strong>on</strong>tally rotating radar, a remotely operated video-camera, a directi<strong>on</strong>al microph<strong>on</strong>e (for recording bird calls),<br />

an ultrasound detector (for recording bat sounds) and an thermal imaging camera to get informati<strong>on</strong> <strong>on</strong> species<br />

compositi<strong>on</strong> and flock sizes during night. Especially the vertical radar collected c<strong>on</strong>tinuous data of the migrating<br />

activities. Additi<strong>on</strong>ally, at several sites <strong>on</strong> the coast and <strong>on</strong> Helgoland observati<strong>on</strong>s of the visible bird migrati<strong>on</strong> are<br />

made.<br />

By combinati<strong>on</strong> of these methods informati<strong>on</strong> is expected <strong>on</strong> migrati<strong>on</strong> directi<strong>on</strong> and intensity in its seas<strong>on</strong>al, diurnal,<br />

weather- and visibility affected and species-specific variability. Additi<strong>on</strong>ally, at several coastal sites the observati<strong>on</strong>s of<br />

the visible bird migrati<strong>on</strong>s are c<strong>on</strong>tinued to get informati<strong>on</strong> <strong>on</strong> phenology and spatial patterns of bird migrati<strong>on</strong> <strong>on</strong> the<br />

species level.<br />

First data collected from the vertically rotating radar have been evaluated and show the flight altitudes corresp<strong>on</strong>ding to<br />

those reported by Hüppop et al., 2002 (see <strong>ICES</strong>, 2003). At least <strong>on</strong>e third of the individuals was migrating below<br />

200 m, in the critical height range of the wind farms. Most radar signals were detected at night, when birds also flew<br />

higher. The c<strong>on</strong>tinuous operati<strong>on</strong> of the vertical radar allowed some first quantificati<strong>on</strong> of reverse migrati<strong>on</strong> for the<br />

southeastern North Sea, i.e., the amount of birds passing the area presumably more than <strong>on</strong>ce. From mid October until<br />

the end of the year (covering almost exclusively short and median distance migrants) roughly 30% of all echoes<br />

recorded during darkness bel<strong>on</strong>ged to birds migrating against the general migrati<strong>on</strong> directi<strong>on</strong>. Reverse migrati<strong>on</strong> was<br />

mainly observed after pr<strong>on</strong>ounced increases in ambient temperature.<br />

10<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


During autumn migrati<strong>on</strong> surprisingly high numbers of bird strikes were recorded <strong>on</strong> FINO 1, almost exclusively<br />

s<strong>on</strong>gbirds (mainly thrushes) with good body c<strong>on</strong>diti<strong>on</strong>.<br />

Following completi<strong>on</strong> of the Envir<strong>on</strong>mental Impact Assessments of the offshore windfarms at Horns Rev and Rødsand<br />

in Denmark, a programme of avian investigati<strong>on</strong>s was established. These included detailed studies during the prec<strong>on</strong>structi<strong>on</strong><br />

(ca. three years), c<strong>on</strong>structi<strong>on</strong> (ca. ½ year) and post-c<strong>on</strong>structi<strong>on</strong> phase (2–3 years). The objective was to<br />

gather base-line data pre-c<strong>on</strong>structi<strong>on</strong> <strong>on</strong> feeding distributi<strong>on</strong>s, migrati<strong>on</strong> trajectories, flight heights and relative volume<br />

of key species in time and space, taking into account annual variati<strong>on</strong> in wind directi<strong>on</strong> and strength, visibility,<br />

disturbance (c<strong>on</strong>structi<strong>on</strong>, operati<strong>on</strong> and maintenance) and time of day. Reports <strong>on</strong> many of these base-line studies have<br />

already been published (see the overview of reports available at<br />

http://www.dmu.dk/1_Om_DMU/2_afdelinger/3_vibi/publikati<strong>on</strong>er1.asp). Now that c<strong>on</strong>structi<strong>on</strong> of both sites have<br />

been completed, m<strong>on</strong>itoring of changes in bird migrati<strong>on</strong> patterns as a result of the presence of the windfarms is<br />

currently underway and these observati<strong>on</strong>s will be reported in due course when the data have been fully analysed.<br />

3.4 Recent progress in site-selecti<strong>on</strong> procedures<br />

One of the problems c<strong>on</strong>cerning marine wind farms is the issue of selecting suitable sites. Without fundamental<br />

informati<strong>on</strong> <strong>on</strong> the effects of wind farms <strong>on</strong> seabirds – due to a lack of truly marine wind farms until very recently – <strong>on</strong>e<br />

approach is to select areas that are least sensitive. Garthe and Hüppop (<strong>2004</strong>) developed a "wind farm sensitivity index"<br />

(WSI) for seabirds. They chose nine factors, derived from species’ attributes, to be included in the WSI: flight<br />

manoeuvrability, flight altitude, percentage of time flying, nocturnal flight activity, sensitivity towards disturbance by<br />

ship and helicopter traffic, flexibility in habitat use, biogeographic populati<strong>on</strong> size, adult survival rate, and European<br />

threat and C<strong>on</strong>servati<strong>on</strong> status. Each factor was scored <strong>on</strong> a five-point-scale from <strong>on</strong>e (low vulnerability of seabirds) to<br />

five (high vulnerability of seabirds). Five of these factors could be dealt with by real data but four could <strong>on</strong>ly be<br />

assessed by subjective c<strong>on</strong>siderati<strong>on</strong>s based <strong>on</strong> at-sea experience; in the latter cases, experts independently modulated<br />

suggesti<strong>on</strong>s of the authors.<br />

Species differed str<strong>on</strong>gly in sensitivity index (Table 3.4.1). Black-throated diver and red-throated diver ranked highest<br />

(= most sensitive), followed by velvet scoter, sandwich tern and great cormorant. Lowest values were calculated for<br />

black-legged kittiwake, black-headed gull and northern fulmar. Derived from the frequency distributi<strong>on</strong> of the WSI<br />

applied to the southeastern North Sea, Garthe and Hüppop (<strong>2004</strong>) suggest a “level of c<strong>on</strong>cern” and a “level of major<br />

c<strong>on</strong>cern” which are visualised spatially and could act as a basis for the selecti<strong>on</strong> of marine wind farm locati<strong>on</strong>s (Figure<br />

3.4.1). The wind farm sensitivity index might be useful in Strategic Envir<strong>on</strong>mental Assessments. Results from smallscale<br />

Envir<strong>on</strong>mental Impact Assessments about wind installati<strong>on</strong>s should be set into a more global perspective provided<br />

for example by large mapping projects and detailed behavioural studies.<br />

3.5 Progress and future plans of m<strong>on</strong>itoring possible impacts of wind farms <strong>on</strong> seabirds<br />

<strong>ICES</strong> (2002) highlights the need for dedicated research in order to assess the potential impact of the c<strong>on</strong>structi<strong>on</strong> of an<br />

offshore wind farm and to understand how such a c<strong>on</strong>structi<strong>on</strong> is likely to affect the birds associated with a site,<br />

dedicated research is required. The coupling of bird census data with geographical, hydrographic and biological<br />

measurements is essential to begin to understand how an offshore c<strong>on</strong>structi<strong>on</strong> such as a wind farm is likely to affect an<br />

area and how the seabirds associated with a site are most likely to resp<strong>on</strong>d. Natural variability issues have also to be<br />

addressed and existing census techniques have been evaluated for their potential to provide data that can be used to<br />

describe habitat characteristics and area usage by seabirds. In 2002, the Crown Estate (UK) initiated a Steering <str<strong>on</strong>g>Group</str<strong>on</strong>g><br />

called COWRIE (Collaborative Offshore Wind Research into the Envir<strong>on</strong>ment) to deal with the envir<strong>on</strong>mental<br />

implicati<strong>on</strong>s of offshore wind farms.<br />

One of the research c<strong>on</strong>tracts awarded was to undertake a comparis<strong>on</strong> of ship and aerial sampling methods for the<br />

mapping of the distributi<strong>on</strong> and abundance of marine birds, and to assess their applicability to offshore windfarm EIAs.<br />

The c<strong>on</strong>tract was awarded to NIOZ (Royal Netherlands Institute for Sea Research), funding a research c<strong>on</strong>sortium<br />

c<strong>on</strong>sisting of the Danish Nati<strong>on</strong>al Envir<strong>on</strong>mental Research Institute, the Wildfowl and Wetlands Trust and the Research<br />

Unit for Wildlife Populati<strong>on</strong> Assessment, St. Andrews University. The c<strong>on</strong>sortium undertook a major review of<br />

techniques and recommended the most appropriate methods to be adopted in UK waters in relati<strong>on</strong> to offshore<br />

windfarm EIAs (Camphuysen et al., in prep.). A workshop gathering interested parties and experts was held in<br />

Aberdeen in November 2003 to discuss the pre–workshop report, the final report of which will be posted <strong>on</strong> the<br />

COWRIE web site when finalised. Background informati<strong>on</strong> can be found <strong>on</strong> the COWRIE web site at<br />

http://www.thecrownestate.co.uk/15_our_portfolio_04_02_16/33_energy_and_telecoms_04_02_09/34_wind_farms_04<br />

_02_07/35_cowrie_04_02_07/35_cowrie_marine_bird_survey_methodology_04_02_07.htm<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 11


The two observati<strong>on</strong> tools discussed by Camphuysen et al. (in prep.) in this study, aerial and ship-based surveys,<br />

potentially provide similar data for as l<strong>on</strong>g as basic seabird counts are c<strong>on</strong>cerned (accurate numbers, accurate maps).<br />

Census techniques are similar (distance techniques using parallel bands of known width), but the level of detail <strong>on</strong><br />

species level is c<strong>on</strong>siderably less during aerial surveys. Aerial surveys are quick and relatively cheap, whereas shipsurveys<br />

are more time-c<strong>on</strong>suming. Data obtained during aerial surveys may be combined with envir<strong>on</strong>mental<br />

parameters in a correlative approach, whereas the advantage of a ship is that such parameters can often be collected<br />

simultaneously. The slower approach with vessels allows detailed observati<strong>on</strong>s <strong>on</strong> seabird behaviour (habitat utilisati<strong>on</strong>,<br />

feeding c<strong>on</strong>diti<strong>on</strong>s) and diurnal/tidal fluctuati<strong>on</strong>s in seabird abundance and distributi<strong>on</strong> (Camphuysen et al. in prep.).<br />

The existing Danish wind farms in Horns Rev (North Sea) and Nysted ( = Rødsand; Baltic Sea) will exhibit substantial<br />

dem<strong>on</strong>strati<strong>on</strong> effects for offshore wind farms in general. Both wind farms may be c<strong>on</strong>sidered being the most<br />

representative for the seas they are located at; Horns Rev is situated off the west coast of Denmark in a marine habitat,<br />

Nysted is placed at a shallow inshore site in the southwestern Baltic Sea. Elsam Engineering plans to c<strong>on</strong>tinue with bird<br />

surveys for at least two years after the commissi<strong>on</strong>ing of the two wind farms. For Nysted, this applies to aerial counts as<br />

well as further developments of methods for study of migrati<strong>on</strong>s. For Horns Rev it is planned to c<strong>on</strong>tinue with aerial<br />

counts for two years and migrati<strong>on</strong> observati<strong>on</strong>s for at least <strong>on</strong>e year, according to the results achieved. For both sites,<br />

efforts are being made to develop collisi<strong>on</strong> detecti<strong>on</strong> methods, but these are not yet effective as a m<strong>on</strong>itoring tool.<br />

3.6 References<br />

Camphuysen, C.J., Fox, A.D., Leopold, M.F., and Petersen, I.K. in prep. Towards standardised seabirds at sea census<br />

techniques in c<strong>on</strong>necti<strong>on</strong> with envir<strong>on</strong>mental impact assessments for offshore wind farms in the U.K. COWRIE-<br />

BAM-02–2002.<br />

Garthe, S., and Hüppop, O. <strong>2004</strong>. Scaling possible adverse effects of marine wind farms <strong>on</strong> seabirds: developing and<br />

applying a vulnerability index. Journal of Applied <strong>Ecology</strong> 41: in press.<br />

Hüppop, O., Exo, K.-M., and Garthe, S. 2002. Empfehlungen für projektbezogene Untersuchungen möglicher bau- und<br />

betriebsbedingter Auswirkungen v<strong>on</strong> Offshore-Windenergieanlagen auf Vögel. Berichte zum Vogelschutz. 39:<br />

77–94.<br />

Hüppop, O., and Exo, M. <strong>2004</strong>. Offshore-Windenergieanlagen und Vögel in Nord- und Ostsee. Jahresbericht des<br />

Instituts für Vogelforschung, 6: 19–20.<br />

<strong>ICES</strong>. 2002. Report of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong>. <strong>ICES</strong> <strong>CM</strong> 2002/C:04.<br />

<strong>ICES</strong>. 2003. Report of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong>. <strong>ICES</strong> <strong>CM</strong> 2003/C:03.<br />

12<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Table 3.4.1. Score of the nine vulnerability factors and the resulting species sensitivity index (SSI) values for each of<br />

the 26 seabird species. For details see Garthe and Hüppop (<strong>2004</strong>).<br />

Bird species Flight<br />

manoeuvra-<br />

bility<br />

Flight<br />

altitude<br />

Percentage<br />

flying<br />

Nocturnal<br />

flight<br />

activity<br />

Disturbance<br />

by ship and<br />

helicopter<br />

traffic<br />

Habitat use<br />

flexibility<br />

Biogeogr.<br />

populati<strong>on</strong><br />

size<br />

Adult<br />

survival<br />

rate<br />

European SSI<br />

threat and<br />

c<strong>on</strong>servati<strong>on</strong><br />

status<br />

Black-throated diver 5 2 3 1 4 4 4 3 5 44,0<br />

Red-throated diver 5 2 2 1 4 4 5 3 5 43,3<br />

Velvet scoter 3 1 2 3 5 4 3 2 3 27,0<br />

Sandwich tern 1 3 5 1 2 3 4 4 4 25,0<br />

Great cormorant 4 1 4 1 4 3 4 3 1 23,3<br />

Comm<strong>on</strong> eider 4 1 2 3 3 4 2 4 1 20,4<br />

Great crested grebe 4 2 3 2 3 4 4 1 1 19,3<br />

Red-necked grebe 4 2 1 1 3 5 5 1 1 18,7<br />

Great black-backed gull 2 3 2 3 2 2 4 5 2 18,3<br />

Black tern 1 1 4 1 2 3 4 4 4 17,5<br />

Comm<strong>on</strong> scoter 3 1 2 3 5 4 2 2 1 16,9<br />

Northern gannet 3 3 3 2 2 1 4 5 3 16,5<br />

Razorbill 4 1 1 1 3 3 2 5 2 15,8<br />

Atlantic puffin 3 1 1 1 2 3 2 5 5 15,0<br />

Comm<strong>on</strong> tern 1 2 5 1 2 3 3 4 1 15,0<br />

Lesser black-backed gull 1 4 2 3 2 1 4 5 2 13,8<br />

Arctic tern 1 1 5 1 2 3 3 4 1 13,3<br />

Little gull 1 1 3 2 1 3 5 2 4 12,8<br />

Great skua 1 3 4 1 1 2 5 4 2 12,4<br />

Comm<strong>on</strong> guillemot 4 1 1 2 3 3 1 4 1 12,0<br />

Mew gull 1 3 2 3 2 2 2 2 4 12,0<br />

Herring gull 2 4 2 3 2 1 2 5 1 11,0<br />

Arctic skua 1 3 5 1 1 2 4 3 1 10,0<br />

Black-headed gull 1 5 1 2 2 2 1 3 1 7,5<br />

Black-legged kittiwake 1 2 3 3 2 2 1 3 1 7,5<br />

Northern fulmar 3 1 2 4 1 1 1 5 1 5,8<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 13


Figure 3.4.1. Areas in the German sector of the North Sea where wind energy utilizati<strong>on</strong> is c<strong>on</strong>sidered to be of “less c<strong>on</strong>cern”,<br />

“c<strong>on</strong>cern” or “major c<strong>on</strong>cern” to seabirds. Areas not studied in at least <strong>on</strong>e of the four seas<strong>on</strong>s are left blank. From Garthe and<br />

Hüppop (<strong>2004</strong>).<br />

4 CLIMATIC EFFECTS ON SEABIRD POPULATION PERFORMANCE<br />

Term of reference: review relati<strong>on</strong>ships between seabirds and oceanographic features, with particular reference to<br />

effects of climate change.<br />

4.1 Introducti<strong>on</strong><br />

<strong>WGSE</strong> in 2003 (<strong>ICES</strong>, 2003) proposed to review relati<strong>on</strong>ships between seabirds and oceanographic features, with<br />

particular reference to effects of climate change. In <strong>2004</strong>, <strong>WGSE</strong> was unable to complete this term of reference, but a<br />

brief review of the effects of climate <strong>on</strong> seabird populati<strong>on</strong> performance was produced. This review collates background<br />

informati<strong>on</strong> that would be useful for future attempts to predict the effects of climate change. <strong>Seabird</strong>s are obviously<br />

affected by numerous natural and anthropogenic factors, such as fisheries, introduced predators, etc., but this review<br />

deals <strong>on</strong>ly with effects of climate. The c<strong>on</strong>clusi<strong>on</strong>s reached here <strong>on</strong> climatic effects should not be taken to imply that<br />

other factors are not important in determining seabird populati<strong>on</strong> growth rate.<br />

The subject of how various aspects of seabird populati<strong>on</strong> performance are affected by climate or oceanography, and<br />

how populati<strong>on</strong>s may react to current and future climate change, has recently attracted much interest. In order to predict<br />

the effects of climate change it is necessary to understand current relati<strong>on</strong>ships between climate and seabird<br />

performance, and this secti<strong>on</strong> intends to provide a preliminary, incomplete review of the recent literature in this field.<br />

Schreiber (2002) recently reviewed how seabirds are affected by the ENSO (El Niño Southern Oscillati<strong>on</strong>), and because<br />

this large-scale climatic event mainly affects the Pacific Ocean as well as tropical regi<strong>on</strong>s, but has little effect in the<br />

north-eastern Atlantic, it will not be c<strong>on</strong>sidered in detail here. Another limitati<strong>on</strong> of this review is that effects <strong>on</strong> the atsea<br />

or breeding distributi<strong>on</strong> of seabirds are not covered. Durant et al. (in press) recently provided a more detailed review<br />

of relati<strong>on</strong>ships between seabirds and climate fluctuati<strong>on</strong>s in the North Atlantic.<br />

14<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


It might be c<strong>on</strong>sidered useful to distinguish between effects of climate and (usually severe) weather <strong>on</strong> seabirds.<br />

However, such a distincti<strong>on</strong> is to some extent artificial, as climate determines the frequency of severe weather events.<br />

This distincti<strong>on</strong> is therefore not adopted here.<br />

Climate can affect seabirds both directly and indirectly. Direct effects of temperature are unlikely to be important for<br />

seabirds in most cases, although chicks of some species may be vulnerable to overheating and dehydrati<strong>on</strong> in warm<br />

summers, and such effects may partly determine the limits of a species' breeding range (Oswald et al. <strong>2004</strong>). Str<strong>on</strong>g<br />

winds are probably more important for many species, mainly because they cause increased turbulence and thus make<br />

prey capture more difficult. Increased flight costs may also be important for some species. In polar and cold temperate<br />

regi<strong>on</strong>s, str<strong>on</strong>g <strong>on</strong>shore winds may also cause hypothermia of chicks, especially if heavy rain occurs at the same time.<br />

The same may occur in winter for adult cormorants (Phalacrocoracidae), which do not have completely waterproof<br />

plumage and must dry out <strong>on</strong> land. Flooding caused by heavy rain sometimes causes egg or chick losses for burrownesting<br />

seabirds, snow cover may prevent access to nest sites or burrows at high latitudes, and ice cover may allow<br />

predators access to otherwise “safe” islands. On the whole, however, indirect effects of climate are likely to be more<br />

important than direct <strong>on</strong>es. These indirect effects often work through the food supply to seabirds. Many marine<br />

foodwebrs are very sensitive to small changes in sea temperature, and even changes as small as 0.5–1° C in annual<br />

means, which are probably too small to affect birds directly, can cause fundamental shifts in the availability of main<br />

seabird prey species. For example, recruitment of lesser sandeels in the North Sea has been found to be low at high<br />

winter sea temperatures (Arnott and Ruxt<strong>on</strong>, 2002). Correlative studies of relati<strong>on</strong>ships between climate and seabird<br />

performance generally do not discriminate between indirect and direct effects, and elucidating the mechanisms behind<br />

observed relati<strong>on</strong>ships will often require further studies. Because physiological requirements of organisms at different<br />

trophic levels can be very different, indirect effects can sometimes create counter-intuitive correlati<strong>on</strong>s, such as high sea<br />

temperatures being unfavourable for polar or temperate seabirds (see examples below).<br />

What we want to draw c<strong>on</strong>clusi<strong>on</strong>s about is whether climate affects, or is likely in the future to affect, the populati<strong>on</strong><br />

size of seabirds. However, because populati<strong>on</strong> size usually changes rather slowly and is affected by a multitude of<br />

processes, it is generally more instructive to search for causal correlati<strong>on</strong>s between, e.g., climate and individual<br />

comp<strong>on</strong>ents of populati<strong>on</strong> performance, which together determine populati<strong>on</strong> size. <strong>Seabird</strong>s are l<strong>on</strong>g-lived organisms,<br />

and as a c<strong>on</strong>sequence their populati<strong>on</strong> growth rate is more sensitive to changes in the survival probability of adult<br />

breeders than in other parameters (Croxall and Rothery, 1991). Nevertheless, successful reproducti<strong>on</strong> and recruitment<br />

are obviously also necessary to maintain a populati<strong>on</strong>, and collecting and analysing data <strong>on</strong> reproducti<strong>on</strong> is often more<br />

simple than <strong>on</strong> survival. Phenology, or the timing of reproducti<strong>on</strong>, is not in itself an aspect of populati<strong>on</strong> performance,<br />

but given the often close relati<strong>on</strong>ship with breeding success and the ease with which data can be collected for many<br />

species, it can nevertheless be useful to test for how phenology is related to climate. Once the relevant data have been<br />

collected, it is reas<strong>on</strong>ably simple to test for correlati<strong>on</strong>s with aspects of climate thought to be important (for<br />

c<strong>on</strong>siderati<strong>on</strong>s about how to select appropriate climate variables, see Secti<strong>on</strong> 4.3 below). Most studies have focussed <strong>on</strong><br />

the relati<strong>on</strong>ship between climate and timing of breeding or breeding success, presumably because more data are<br />

available <strong>on</strong> these parameters and analyses are simpler. However, a few studies have started looking at the complex, but<br />

potentially very important, relati<strong>on</strong>s between climate and adult or juvenile survival.<br />

4.2 Relati<strong>on</strong>s between seabird populati<strong>on</strong> performance and climate<br />

4.2.1 Phenology<br />

Several studies have found clear relati<strong>on</strong>ships between inter-annual variati<strong>on</strong> in the timing of breeding in seabirds and<br />

some measure of climate. In most cases, breeding was earlier following milder winter c<strong>on</strong>diti<strong>on</strong>s, either locally or<br />

regi<strong>on</strong>ally. The classical study of Aebischer et al. (1990) showed that timing of egg-laying in black-legged kittiwakes<br />

was related to the frequency of westerly weather <strong>on</strong> an annual basis. Gjerdrum et al. (2003) found that breeding in<br />

tufted puffins was earlier when local sea surface temperature (SST) during chick-rearing was high, although it is unclear<br />

how birds were assumed to adjust their phenology to achieve this. In Atlantic puffins, Diam<strong>on</strong>d and Devlin (2003)<br />

interpreted the earlier breeding in Maine, USA than in N Norway as a c<strong>on</strong>sequence of higher May SST in Maine, with<br />

the slope of the relati<strong>on</strong>ship being similar to the <strong>on</strong>e found in N Norway by Barrett (2001). Frederiksen et al. (in press)<br />

found that breeding of three seabird species was earlier following mild winters, measured as local late winter SST or the<br />

North Atlantic Oscillati<strong>on</strong> (NAO) winter index. In Atlantic puffins in Norway, breeding was also earlier following mild<br />

winters (i.e., when the NAO index was high), except during 1987–1994 (Durant et al., <strong>2004</strong>). There are some<br />

indicati<strong>on</strong>s that breeding phenology can be influenced by very large-scale processes; in roseate terns breeding in the<br />

tropical Indian Ocean, Ramos et al. (2002) found that timing of breeding was correlated with an index of ENSO, even<br />

though this index was based <strong>on</strong> measurements from the Pacific Ocean. L<strong>on</strong>g-term trends in phenology seem to vary<br />

between study sites, with breeding getting progressively earlier in tufted puffins in the Pacific (Gjerdrum et al., 2003),<br />

but later in North Sea black-legged kittiwakes and comm<strong>on</strong> guillemots (Aebischer et al. 1990; Frederiksen et al., in<br />

press).<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 15


4.2.2 Breeding success<br />

It is a general finding in birds that early breeding is advantageous, so it is hardly surprising that several of the abovementi<strong>on</strong>ed<br />

studies found that breeding success was related to the same climatic factors as phenology (Aebischer et al.,<br />

1990; Ramos et al., 2002). Durant et al. (2003) found that breeding success in Atlantic puffins was related to SST in a<br />

sigmoid fashi<strong>on</strong>, while NAO had no effect. However, in tufted puffins there was a curvilinear relati<strong>on</strong>ship, with<br />

breeding success being low at both the highest and lowest values of SST (Gjerdrum et al., 2003), and Diam<strong>on</strong>d and<br />

Devlin (2003) found no relati<strong>on</strong>ship between SST and breeding success. Despite low chick growth rates, horned puffin<br />

breeding success in Alaska was high during year of ENSO-related low food availability (Harding et al., 2003). Inchausti<br />

et al. (2003) found varying relati<strong>on</strong>ships between SST and breeding success for eight seabird species at the sub-<br />

Antarctic Kerguelen and Crozet Islands: species foraging north of the Polar Fr<strong>on</strong>t (wandering albatross, sooty albatross)<br />

had high breeding success when SST was high, whereas those foraging south of the Polar Fr<strong>on</strong>t (light-mantled sooty<br />

albatross, blue petrel, thin-billed pri<strong>on</strong>, white-headed petrel) showed the reverse relati<strong>on</strong>ship, and breeding success of<br />

species foraging close to the islands (black-browed albatross, grey petrel) was independent of SST (Inchausti et al.,<br />

2003). In southern fulmars, breeding success was low when sea ice c<strong>on</strong>centrati<strong>on</strong> around the col<strong>on</strong>y was low, as was<br />

recruitment of new adults to the breeding populati<strong>on</strong> (Jenouvrier et al., 2003). In the closely related northern fulmar,<br />

Thomps<strong>on</strong> and Ollas<strong>on</strong> (2001) found that breeding success was weakly negatively correlated with the NAO index,<br />

indicating low breeding success following mild winters; they also found that the proporti<strong>on</strong> of a birth cohort recruiting<br />

to the breeding populati<strong>on</strong> depended <strong>on</strong> a global measure of summer temperatures in the northern hemisphere.<br />

As an example of a direct effect, breeding success of Manx shearwaters <strong>on</strong> Rum was str<strong>on</strong>gly affected by rainfall during<br />

the breeding seas<strong>on</strong>, and was particularly low when heavy rainfall was frequent (Thomps<strong>on</strong> and Furness, 1991).<br />

4.2.3 Survival<br />

Relating survival to climatic or oceanographic variables has proved to be c<strong>on</strong>siderably more challenging, or at least,<br />

<strong>on</strong>ly few published studies to date have shown such correlati<strong>on</strong>s. In blue petrels in the southern Indian Ocean, winter<br />

survival was str<strong>on</strong>gly related to lagged variati<strong>on</strong> in the Southern Oscillati<strong>on</strong> Index, with survival being low during years<br />

when SST was higher than normal (Barbraud and Weimerskirch, 2003). Climate interacted with populati<strong>on</strong> size so that<br />

when a series of warm years occurred when populati<strong>on</strong> size was high, survival became very low and the populati<strong>on</strong><br />

crashed (Barbraud and Weimerskirch, 2003). In high-Antarctic southern fulmars, Jenouvrier et al. (2003) also found a<br />

negative effect of winter SST <strong>on</strong> adult survival and attributed this to climatic effects <strong>on</strong> food availability. J<strong>on</strong>es et al.<br />

(2002) found that survival of least auklets in the Pacific was related to an index of winter ocean climate throughout the<br />

species’ range.<br />

4.3 Scale issues<br />

It seems reas<strong>on</strong>able to assume that the geographical scale at which seabirds are affected most directly by climate, and<br />

thus where the str<strong>on</strong>gest correlati<strong>on</strong>s are found, should be the <strong>on</strong>e at which the birds interact with their envir<strong>on</strong>ment.<br />

Using climate variables measured at the “wr<strong>on</strong>g” scale, or in the wr<strong>on</strong>g place, is likely to lead to underestimati<strong>on</strong> of the<br />

strength of interacti<strong>on</strong>s between seabirds and climatic factors. Nevertheless, very few studies have explicitly c<strong>on</strong>sidered<br />

the issue of scale. J<strong>on</strong>es et al. (2002) found that adult survival of least auklets was correlated with climatic fluctuati<strong>on</strong>s<br />

at the meso-scale, but not with a basin-wide index. Frederiksen et al. (in press) found that correlati<strong>on</strong>s between<br />

phenology and climate in three North Sea seabirds depended <strong>on</strong> the species-specific n<strong>on</strong>-breeding distributi<strong>on</strong>. In two<br />

dispersive species, comm<strong>on</strong> guillemot and black-legged kittiwake, phenology was related to the NAO index, whereas a<br />

resident species, the European shag, bred earlier when local late-winter SST was high.<br />

In this c<strong>on</strong>text, it is important to c<strong>on</strong>sider carefully which climate variables <strong>on</strong>e tries to relate seabird performance to.<br />

Using “standard” indices of large-scale processes, such as NAO and ENSO, may be tempting, because they are easily<br />

available and seem to allow more general c<strong>on</strong>clusi<strong>on</strong>s to be drawn. However, birds are more likely to react to c<strong>on</strong>diti<strong>on</strong>s<br />

at the time and place they actually encounter them, and the str<strong>on</strong>gest correlati<strong>on</strong>s should therefore be expected at this<br />

scale. Because climate variables at different scales are often intercorrelated, using the “wr<strong>on</strong>g” variables may lead to<br />

partially misleading c<strong>on</strong>clusi<strong>on</strong>s about causal relati<strong>on</strong>ships. However, in pelagic seabirds, the areas used outside the<br />

breeding seas<strong>on</strong> are often huge and not known in detail, and using large-scale indices is probably the best available<br />

approach to correlating, e.g., overwinter survival of these species with climate.<br />

4.4 C<strong>on</strong>clusi<strong>on</strong>s<br />

The field of seabird-climate interacti<strong>on</strong>s is a very dynamic <strong>on</strong>e, and this short review does not claim to provide a full<br />

overview of all the published research; particularly, there is a bias towards very recent papers. However, it is clear that<br />

an increasing number of researchers are both looking for and finding correlati<strong>on</strong>s between various aspects of seabird<br />

16<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


performance and climatic variables, and it is likely that at least some failures to find such correlati<strong>on</strong>s are related to the<br />

use of inappropriate measures of climatic variati<strong>on</strong>. Most of the authors of the studies reviewed here either explicitly or<br />

implicitly interpret climate effects <strong>on</strong> seabirds as being indirect, i.e., mainly working through effects <strong>on</strong> food<br />

availability or quality. If seabird breeding success and survival are indeed affected by climate, as much of the evidence<br />

reviewed here seems to suggest, we should expect current and future climate change to have substantial effects <strong>on</strong><br />

populati<strong>on</strong> size, as well as <strong>on</strong> breeding and wintering distributi<strong>on</strong>. In the North Sea, there is str<strong>on</strong>g evidence for a<br />

“regime shift” taking place in the late 1980s, when increasing SST led to fundamental changes in plankt<strong>on</strong><br />

communities. Such effects are likely to have been propagated through the foodwebr to top predators such as seabirds,<br />

and we should expect to find changes in populati<strong>on</strong> parameters taking place around that time, perhaps with a delay of<br />

some years. Whether such changes are str<strong>on</strong>g enough to cause sustained declines or increases of seabirds in the North<br />

Sea and adjoining areas remains to be seen.<br />

4.5 Summary<br />

• Climate is <strong>on</strong>e of many factors affecting seabird populati<strong>on</strong> performance; others such as fisheries and introduced<br />

predators may be more or less important depending <strong>on</strong> the c<strong>on</strong>text;<br />

• Effects may be either direct, physiological impacts <strong>on</strong> birds, or indirect effects often through food supply;<br />

• <strong>Seabird</strong> populati<strong>on</strong> size and growth rate are determined by the balance of reproducti<strong>on</strong> and survival; reproductive<br />

success is often str<strong>on</strong>gly influenced by timing of breeding (phenology);<br />

• Predicting the effects of climate change <strong>on</strong> seabird populati<strong>on</strong>s requires an understanding of how current climate<br />

affects populati<strong>on</strong> performance;<br />

• Most studies looking for climatic effects <strong>on</strong> seabird populati<strong>on</strong>s have found such effects;<br />

• Studies looking for relati<strong>on</strong>ships between climate and populati<strong>on</strong> performance often cannot distinguish between<br />

direct and indirect effects;<br />

• Many studies have found correlati<strong>on</strong>s between phenology and climate, most often with breeding being earlier<br />

following mild winters;<br />

• Relati<strong>on</strong>ships between breeding success and climate are variable, e.g., different studies have found positive,<br />

negative and no effects of sea temperature <strong>on</strong> success;<br />

• There are few studies of effects of climate <strong>on</strong> survival; some of these have found survival to be low in warm<br />

winters;<br />

• Climatic variables should be measured at the most appropriate scale, i.e., <strong>on</strong>e corresp<strong>on</strong>ding to how seabirds<br />

perceive and use their envir<strong>on</strong>ment.<br />

4.6 References<br />

Aebischer, N.J., Couls<strong>on</strong>, J.C. and Colebrook, J.M. 1990. Parallel l<strong>on</strong>g-term trends across four marine trophic levels<br />

and weather. Nature, 347: 753–755.<br />

Arnott, S.A., and Ruxt<strong>on</strong>, G.D. 2002. Sandeel recruitment in the North Sea: demographic, climatic and trophic effects.<br />

Marine <strong>Ecology</strong> Progress Series, 238: 199–210.<br />

Barbraud, C. and Weimerskirch, H. 2003. Climate and density shape populati<strong>on</strong> dynamics of a marine top predator.<br />

Proceedings of the Royal Society of L<strong>on</strong>d<strong>on</strong> Series B, 270: 2111–2116.<br />

Barrett, R.T. 2001. The breeding demography and egg size of North Norwegian Atlantic puffins Fratercula arctica and<br />

razorbills Alca torda during twenty years of climatic variability. Atlantic <strong>Seabird</strong>s, 3: 97–112.<br />

Croxall, J.P., and Rothery, P. 1991. Populati<strong>on</strong> regulati<strong>on</strong> of seabirds: implicati<strong>on</strong>s of their demography for<br />

c<strong>on</strong>servati<strong>on</strong>. In Bird populati<strong>on</strong> studies. Relevance to c<strong>on</strong>servati<strong>on</strong> and management. Ed. by Perrins, C.M.,<br />

Lebret<strong>on</strong>, J.-D. and Hir<strong>on</strong>s, G.J.M. Oxford University Press, Oxford: 272–296.<br />

Diam<strong>on</strong>d, A.W., and Devlin, C.M. 2003. <strong>Seabird</strong>s as indicators of changes in marine ecosystems: ecological m<strong>on</strong>itoring<br />

<strong>on</strong> Machias Seal Island. Envir<strong>on</strong>mental M<strong>on</strong>itoring and Assessment, 88: 153–175.<br />

Durant, J.M., Anker-Nilssen, T., and Stenseth, N.C. 2003. Trophic interacti<strong>on</strong>s under climate fluctuati<strong>on</strong>s: the Atlantic<br />

puffin as an example. Proceedings of the Royal Society of L<strong>on</strong>d<strong>on</strong> Series B, 270: 1461–1466.<br />

Durant, J.M., Anker-Nilssen, T., Hjermann, D.Ø., and Stenseth, N.C. <strong>2004</strong>. Regime shifts in the breeding of an Atlantic<br />

puffin populati<strong>on</strong>. <strong>Ecology</strong> Letters, 7: 388-394.<br />

Durant, J.M., Stenseth, N.C., Anker-Nilssen, T., Harris, M.P., Thomps<strong>on</strong>, P.M., and Wanless, S. In press b. Marine<br />

birds and climate fluctuati<strong>on</strong>s in the North Atlantic. In Marine ecosystems and climate variati<strong>on</strong> – the North<br />

Atlantic. Ed. by Stenseth, N.C., Ottersen, G., Hurrell, J.W. and Belgrano, A. Oxford University Press, Oxford: 95–<br />

1<strong>05</strong>.<br />

Frederiksen, M., Harris, M.P., Daunt, F., Rothery, P. and Wanless, S. In press. Scale-dependent climate signals drive<br />

breeding phenology of three seabird species. Global Change Biology.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 17


Gjerdrum, C.G., Vallée, A.M.J., St. Clair, C.C., Bertram, D.F., Ryder, J.L. and Blackburn, G.S. 2003. Tufted puffin<br />

reproducti<strong>on</strong> reveals ocean climate variability. Proceedings of the Nati<strong>on</strong>al Academy of Science of the USA, 100:<br />

9377–9382.<br />

Harding, A.M.A., Piatt, J.F. and Hamer, K.C. 2003. Breeding ecology of horned puffins (Fratercula corniculata) in<br />

Alaska: annual variati<strong>on</strong> and effects of El Niño. Canadian Journal of Zoology, 81: 1004–1013.<br />

<strong>ICES</strong>. 2003. Report of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong>. <strong>ICES</strong> <strong>CM</strong> 2003/C:03.<br />

Inchausti, P., Guinet, C., Koudil, M., Durbec, J.-P., Barbraud, C., Weimerskirch, H., Cherel, Y., and Jouventin, P. 2003.<br />

Inter-annual variability in the breeding performance of seabirds in relati<strong>on</strong> to oceanographic anomalies that affect<br />

the Crozet and the Kerguelen sectors of the Southern Ocean. Journal of Avian Biology, 34: 170–176.<br />

Jenouvrier, S., Barbraud, C., and Weimerskirch, H. 2003. Effects of climate variability <strong>on</strong> the temporal populati<strong>on</strong><br />

dynamics of southern fulmars. Journal of Animal <strong>Ecology</strong>, 72: 576–587.<br />

J<strong>on</strong>es, I.L., Hunter, F.M., and Roberts<strong>on</strong>, G.J. 2002. Annual adult survival of least auklets (Aves, Alcidae) varies with<br />

large scale climatic c<strong>on</strong>diti<strong>on</strong>s in the North Pacific Ocean. Oecologia, 133: 38–44.<br />

Oswald, S., Huntley, B., and Hamer, K.C. <strong>2004</strong>. Exploring the impact of climate <strong>on</strong> the distributi<strong>on</strong> of great skuas<br />

breeding in the UK. Abstract, 8 th Internati<strong>on</strong>al <strong>Seabird</strong> <str<strong>on</strong>g>Group</str<strong>on</strong>g> C<strong>on</strong>ference, Aberdeen, 2–4 April <strong>2004</strong>.<br />

Ramos, J.A., Maul, A.M., Ayrt<strong>on</strong>, V., Bullock, I., Hunter, J., Bowler, J., Castle, G., Mileto, R., and Pacheco, C. 2002.<br />

Influence of local and large-scale weather events and timing of breeding <strong>on</strong> tropical roseate tern reproductive<br />

parameters. Marine <strong>Ecology</strong> Progress Series, 243: 271–279.<br />

Schreiber, E.A. 2002. Climate and weather effects <strong>on</strong> seabirds. In Biology of marine birds. Ed. By Schreiber, E.A. and<br />

Burger, J. CRC Press, Boca Rat<strong>on</strong>, Florida: 179–216.<br />

Thomps<strong>on</strong>, K.R., and Furness, R.W. 1991. The influence of rainfall and nest site quality <strong>on</strong> the populati<strong>on</strong> dynamics of<br />

the Manx shearwater Puffinus puffinus <strong>on</strong> Rhum. Journal of Zoology, L<strong>on</strong>d<strong>on</strong>, 225: 427–437.<br />

Thomps<strong>on</strong>, P.M., and Ollas<strong>on</strong>, J.C. 2001. Lagged effects of ocean climate change <strong>on</strong> fulmar populati<strong>on</strong> dynamics.<br />

Nature 413: 417–420.<br />

5 A COMPARISON OF SEABIRD COMMUNITIES AND PREY CONSUMPTION IN THE EAST<br />

AND WEST NORTH ATLANTIC<br />

Term of reference: complete the work carried out in 2003 to compare seabird communities and prey c<strong>on</strong>sumpti<strong>on</strong><br />

between the east and west North Atlantic.<br />

5.1 Introducti<strong>on</strong><br />

The <strong>WGSE</strong> 2002 meeting completed a summary of the breeding seabird numbers by species, total seabird energy<br />

requirements and approximate food c<strong>on</strong>sumpti<strong>on</strong> equivalents, in all <strong>ICES</strong> areas (approximately described as the ‘east<br />

North Atlantic’). Given the pr<strong>on</strong>ounced differences in seabird community compositi<strong>on</strong> and species abundances, and in<br />

fish stocks and fisheries, between the west and east North Atlantic, <strong>WGSE</strong> 2003 thought that it might be instructive to<br />

compare and c<strong>on</strong>trast the patterns of seabird community compositi<strong>on</strong> and energy requirements between <strong>ICES</strong> and<br />

NAFO areas (approximately ‘east’ and ‘west’ North Atlantic), in relati<strong>on</strong> to broad differences in the histories of fish<br />

stocks and fisheries in these areas. We here complete the comparis<strong>on</strong> of the seabird communities and their c<strong>on</strong>sumpti<strong>on</strong><br />

<strong>on</strong> both sides of the North Atlantic. The relati<strong>on</strong>ships to fish stocks and fisheries need to be followed up.<br />

5.1.1 Populati<strong>on</strong> estimates<br />

The estimates of numbers presented here are primarily of birds nesting <strong>on</strong> the coast and feeding wholly or partially at<br />

sea, but the numbers of gulls may also include a small fracti<strong>on</strong> of n<strong>on</strong>-marine, inland-breeding segments of the<br />

populati<strong>on</strong>s. They are based <strong>on</strong> the input by members of the <strong>WGSE</strong> who were asked to provide the best estimates of the<br />

numbers of seabirds currently breeding in their respective countries. Some of these are now several years old, and<br />

predate recent nati<strong>on</strong>al updates. The background data are presented in earlier <strong>WGSE</strong> reports. Although a number of<br />

known caveats have been c<strong>on</strong>sidered here, discrepancies from an updated analysis of the database would probably be<br />

small.<br />

Data from the huge col<strong>on</strong>ies of, e.g., northern fulmars, guillemots, little auks and Atlantic puffins in Canada, Greenland,<br />

Iceland, Svalbard and the Barents Sea should not be c<strong>on</strong>sidered as definitive. Some are quoted as “guesstimates” and<br />

await more detailed censuses. Furthermore, while data for many species were presented to the nearest hundred, ten or<br />

even individual pairs, others were presented as ranges, some as large as 100,000–1,000,000 pairs. For the sake of<br />

simplicity, all such ranges were tabulated as mid-points between the two extremes.<br />

18<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Calculati<strong>on</strong> of numbers of birds in the n<strong>on</strong>-breeding part of populati<strong>on</strong><br />

Whereas the numbers of breeding adults were generally known or estimated based <strong>on</strong> field data, numbers<br />

of nestlings and pre-breeders were estimated empirically using a classificati<strong>on</strong> of whether the species lay<br />

single or multiple-egg clutches, and calculati<strong>on</strong>s based numbers of breeding pairs (bp) plus numbers of<br />

immatures (calculated for single-egg species = (bp x 0.7) + (bp x 0.7); multi-egg species = (bp x 0.6) +<br />

(bp x 1). These estimates assumed that numbers of n<strong>on</strong>-breeding birds (immatures and deferred breeders)<br />

were equivalent to 35% or 30% of the breeding populati<strong>on</strong> and that the fledging success of single-egg and<br />

multi-egg clutch species was 0.7 and 1.0 chicks/pair, respectively (Cairns et al. 1991).<br />

These calculati<strong>on</strong>s are very crude, and do not take into c<strong>on</strong>siderati<strong>on</strong> populati<strong>on</strong> trends or life histories of<br />

the different species. In the calculati<strong>on</strong>s of seas<strong>on</strong>al changes in total numbers (and hence biomass and<br />

food c<strong>on</strong>sumpti<strong>on</strong>) of birds in a populati<strong>on</strong> (i.e., breeding pairs + immatures), the resulting figures have<br />

been used for the whole year, and no correcti<strong>on</strong> has been made to account for the fact that reproducti<strong>on</strong><br />

takes place during summer and mortality takes place during the year. As a result, the autumn populati<strong>on</strong><br />

sizes will be underestimated and spring populati<strong>on</strong> sizes will be overestimated. For single-egg species<br />

these under- and overestimates will each be about 10%, and for multi-egg species about 20%.<br />

Of the many species of divers, ducks and geese, some of which may be equally defined as seabirds as some of the gulls,<br />

<strong>on</strong>ly the eider duck is included as a breeding species due to its total dependence <strong>on</strong> the sea for food, and to their very<br />

large numbers in some areas. Other waterfowl which breed inland but feed in the sea in large numbers at other times of<br />

the year are, however, c<strong>on</strong>sidered where relevant. Data sources were Anker-Nilssen et al. (2000), Delany and Scott<br />

(2002), Durinck et al. (1994), Gilchrist (pers. com.), Gilliland (pers.com.), Hagemeijer and Blair (1997), Kershaw and<br />

Cranswick (2003) Merkel et al. (2002), Mosbech and Boertmann (1999), Nygård et al. (1988) and Savard (pers.com.).<br />

At the other end of the scale, some rare species whose total numbers do not total more than a few hundred (e.g., gullbilled<br />

tern, Sabine’s gull) are not included in the calculati<strong>on</strong>s.<br />

In additi<strong>on</strong> to birds that breed in specific <strong>ICES</strong> and NAFO areas, there are, at times, large numbers that breed outside<br />

the areas but are present at certain times of the year as migratory or wintering populati<strong>on</strong>s. Furthermore birds breeding<br />

within the <strong>ICES</strong> and NAFO areas may also move to other areas during migrati<strong>on</strong> or to spend the winter. We have<br />

attempted to account for these movements by estimating the occurrence by m<strong>on</strong>th for each species in each subarea and<br />

making rough estimates of the numbers of individuals present. The resulting numbers were summed by seas<strong>on</strong> by<br />

dividing the year into four quarters. The summer seas<strong>on</strong> in <strong>ICES</strong> and NAFO was chosen separately so the summer<br />

included all the species breeding seas<strong>on</strong>s as far as possible. The resulting seas<strong>on</strong>s differed by two m<strong>on</strong>th between <strong>ICES</strong><br />

and NAFO because of the climatic and hence phenological diffences. In the <strong>ICES</strong> regi<strong>on</strong> winter was defined as Nov-<br />

Jan, spring Feb-Apr, summer May-July and autumn Aug-Oct. In NAFO, winter was defined as Jan-Mar, spring Apr-<br />

June, summer July-Sep and autumn Oct-Dec. Migrati<strong>on</strong> tendency and routes of the various species in <strong>ICES</strong> areas were<br />

taken from Anker-Nilssen et al. (2000), Bakken et al. (2003), Lyngs (2003), Petersen (1982), and Wernham et al.<br />

(2002). These estimates were limited to the comm<strong>on</strong>est species breeding within a given area, i.e., species whose<br />

biomass c<strong>on</strong>stituted > 2% of the original estimate of the total biomass of seabirds breeding in that area (based <strong>on</strong> Tables<br />

2.1–2.5, <strong>ICES</strong> 2002). For NAFO, the seas<strong>on</strong>al movements of seabirds are based mainly <strong>on</strong> Diam<strong>on</strong>d et al. (1993),<br />

Huettmann (pers. com.) and Lyngs (2003).<br />

5.1.2 C<strong>on</strong>sumpti<strong>on</strong><br />

The annual c<strong>on</strong>sumpti<strong>on</strong> by seabirds in a given area was estimated using calculated species-specific energy demands,<br />

numbers of individuals of that species within that area, number of days present and a mean energy density of food set at<br />

5.5 kJ/g (see box below). Like the calculati<strong>on</strong>s of bird numbers, this was modelled separately for the four seas<strong>on</strong>s and<br />

summed for the year.<br />

Daily and hence seas<strong>on</strong>al energy demands were calculated using the methods described in Barrett et al. (2002) – see<br />

box below.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 19


Energy expenditure<br />

Basal metabolic rates were estimated using Gabrielsen’s (1994) allometric equati<strong>on</strong>s for Procellariiformes<br />

(BMR=377.9m 0.7<strong>05</strong> , m in kg) and for seabirds using flapping flight in cold waters (the remaining species<br />

BMR=455.1 m 0.746 , m in kg). Field metabolic rates of breeding birds within the breeding seas<strong>on</strong> were<br />

estimated for Procellariiformes using the allometric equati<strong>on</strong>, FMR=18.4m 0.599 (m in g) from Nagy et al.<br />

(1999) and for the remaining species using the allometric equati<strong>on</strong> for seabirds using flapping flight in cold<br />

waters (FMR=11.455m 0.727 ), m in g; Birt-Friesen et al. 1989). For seaducks, the equati<strong>on</strong>s for ‘all seabirds’<br />

were used.<br />

For the n<strong>on</strong>-breeding part of the breeding populati<strong>on</strong> (chicks, immatures and deferred breeders) during the<br />

breeding seas<strong>on</strong> and for all birds outside the breeding seas<strong>on</strong>, FMR was set as 2.5 x BMR (Gales and Green<br />

1990, Gabrielsen G.W. pers. comm.). The energy expenditure for breeding seabirds was thus calculated<br />

separately within the breeding seas<strong>on</strong> (using the largest FMR values) and outside the breeding seas<strong>on</strong>, and<br />

for n<strong>on</strong>-breeding birds throughout the period they occupied the area in questi<strong>on</strong> using the lower FMR<br />

values. These were then summed to give the overall energy expenditure of a given species within a given<br />

seas<strong>on</strong>.<br />

The length of the breeding seas<strong>on</strong> was set as the incubati<strong>on</strong> period + fledging period (in days, as given in<br />

Cramp and Simm<strong>on</strong>s, 1977, 1983; Cramp, 1985) + 20 days (see Appendix 5.1 for an example from <strong>ICES</strong><br />

Va, Iceland).<br />

In the model used in 2002 (<strong>ICES</strong> 2002), a mean energy density of 6.0 kJ/g (wet mass) and a digesti<strong>on</strong> efficiency of 75%<br />

were used in the calculati<strong>on</strong>s of food c<strong>on</strong>sumpti<strong>on</strong>. When comparing the results with those using a model in which<br />

species-specific diet compositi<strong>on</strong> (fatty fish, lean fish or invertebrates) and digesti<strong>on</strong> efficiency is entered (e.g., Barrett<br />

et al., 2002), it becomes evident that a mean energy density of 6.0 kJ/g is too high. A value of 5.5 kJ/g results in a closer<br />

harm<strong>on</strong>izati<strong>on</strong> of the final c<strong>on</strong>sumpti<strong>on</strong> figures in the two models. Because diet compositi<strong>on</strong> is largely unknown in<br />

many species in most of the <strong>ICES</strong> and NAFO areas, an overall energy density of 5.5 kJ/g and a digesti<strong>on</strong> efficiency of<br />

75% were thus used in the present model.<br />

5.2 Results<br />

5.2.1 Breeding populati<strong>on</strong>s (adapted from <strong>ICES</strong> 2003)<br />

Approximately 67 milli<strong>on</strong> pairs of seabirds breed al<strong>on</strong>g the coasts of the NAFO and <strong>ICES</strong> areas of the North Atlantic.<br />

Note that this does not include the ca. 3.5–4 milli<strong>on</strong> pairs (mostly Brünnich’s guillemots) that breed in the eastern<br />

Canadian Arctic, west of NAFO 0.<br />

Of this 70+ milli<strong>on</strong> pairs, approx. 40 milli<strong>on</strong> breed in the NAFO subareas compared to approx. 27 milli<strong>on</strong> pairs in the<br />

<strong>ICES</strong> subareas (<strong>ICES</strong> 2002, 2003). However, the total biomass of seabirds that breed in the western North Atlantic (ca.<br />

30,000 t) is approximately half that of the eastern North Atlantic (ca. 60,000 t) (<strong>ICES</strong> 2002, 2003). This anomaly is due<br />

to the huge numbers of the small-sized little auks and Leach’s storm-petrels which dominate the breeding communities<br />

in NAFO 1 and NAFO 2 and 3 respectively.<br />

Auks dominate the seabirds breeding <strong>on</strong> both sides of the Atlantic (Tables 5.1 and 5.2). In Western Greenland (NAFO<br />

1), 33 milli<strong>on</strong> pairs of little auks comprise ca. 80% of total breeding populati<strong>on</strong> and ca. 65% of total biomass of all<br />

seabirds in the NAFO subareas. In the <strong>ICES</strong> subareas, puffins, little auks, comm<strong>on</strong> and Brünnich’s guillemots make up<br />

22%, 18%, 9% and 9% (by number) of the total populati<strong>on</strong>s. In biomass, the c<strong>on</strong>tributi<strong>on</strong> by little auks falls to 5% while<br />

that of the larger species is between 13–16%. As in the western Atlantic, the majority (> 70%) of the auks in the <strong>ICES</strong><br />

areas breed in the northernmost subareas, north of the 5° C July isotherm.<br />

The procellariiformes are also very unevenly distributed with a dominance (60–65% of <strong>ICES</strong> procellariiformes by no.<br />

and biomass) in the southern part of the <strong>ICES</strong> subareas (VIIIa-c, IXa and X – mostly Cory’s shearwaters) and 80% of<br />

NAFO procellariiformes by number but <strong>on</strong>ly 20% by biomass in Newfoundland and Labrador (NAFO 2 and 3). The<br />

relatively minor biomass in NAFO 2 and 3 is due to the small size of the Leach’s storm-petrel (it weighs ca. 50 g) that<br />

dominates the NAFO breeding populati<strong>on</strong> by number. Northern fulmars and Manx shearwaters also made up large<br />

proporti<strong>on</strong>s of numbers (41%) and biomass (30%) of the seabirds breeding in the Faeroes and the western borders of the<br />

UK. Fulmars are also very numerous <strong>on</strong> Iceland (<strong>ICES</strong> Va, estimated to be 1.5 mill. pairs).<br />

20<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Table 5.1. Relative species compositi<strong>on</strong> of seabirds breeding in the <strong>ICES</strong> subareas as % of total number and total biomass of<br />

breeding pairs for each subarea (from <strong>ICES</strong>, 2003).<br />

Species<br />

compositi<strong>on</strong><br />

% by number Barents and<br />

Norwegian Seas<br />

I,IIa,IIb Va,XIVa,b IVa-c,VIId,e IIIa-d Vb,VIa,b,f,g,j VIIIa-c,<br />

IXa,X<br />

E. Greenland<br />

and Iceland<br />

North Sea and<br />

English<br />

Channel<br />

Baltic Sea,<br />

Skagerrak, and<br />

Kattegat<br />

Faeroes and<br />

western UK<br />

Petrels 9 15 12 0 41 64<br />

Pelecaniformes < 1 < 1 4 7 5 1<br />

Eiders 2 3 2 40 < 1 0<br />

Gulls 16 6 40 41 14 30<br />

Terns 1 2 4 8 < 1 4<br />

Auks 70 73 38 4 39 < 1<br />

% by biomass<br />

Petrels 12 21 12 0 30 61<br />

Pelecaniformes 2 2 16 16 22 3<br />

Eiders 6 8 3 60 < 1 0<br />

Gulls 14 6 30 21 11 36<br />

Terns < 1 < 1 1 1 < 1 1<br />

Auks 65 62 38 2 37 < 1<br />

France,<br />

Iberia, and<br />

Azores<br />

Table 5.2. Relative species compositi<strong>on</strong> of seabirds breeding in the NAFO areas as% of total number and total biomass of breeding<br />

pairs for each subarea (from <strong>ICES</strong>, 2003).<br />

Species compositi<strong>on</strong> 0 1 2 and 3 4 5 6<br />

% by number<br />

Eastern Baffin<br />

Island<br />

West<br />

Greenland<br />

East NFL and<br />

Labrador<br />

Gulf of St.<br />

Lawrence and<br />

Scotian Shelf<br />

Gulf of<br />

Maine<br />

Petrels 15 < 1 80 9 11 0<br />

Eiders < 1 0 < 1 10 15 0<br />

Pelicaniformes 0 0 < 1 21 20 1<br />

Gulls 5 < 1 2 37 45 70<br />

Terns 0 < 1 < 1 6 7 29<br />

Auks 79 99 16 17 2 0<br />

% by biomass<br />

Petrels 13 1 19 < 1 < 1 0<br />

Eiders 2 < 1 4 19 27 0<br />

Pelicaniformes 0 < 1 7 43 27 4<br />

Gulls 2 2 8 25 45 88<br />

Terns 0 < 1 < 1 < 1 < 1 8<br />

Auks 83 96 62 12 < 1 0<br />

L<strong>on</strong>g Island to<br />

Cap Hatteras<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 21


The pelecaniformes (cormorants, shags and gannets) seem to be more important in NAFO 4 and 5 (where they make up<br />

20% by number and 30–45% by biomass respectively) than in any other NAFO or <strong>ICES</strong> subarea. In the eastern North<br />

Atlantic they c<strong>on</strong>stitute <strong>on</strong>ly 5–7% by number and 16–22% by biomass in the areas compassing the North Sea and<br />

English Channel (IVa-c, VIId,e) and the Faeroes and western UK (Vb, VIa,b,f,g,j) (Table 5.1)<br />

C<strong>on</strong>stituting 40% and 41% by number and 60% and 21% by biomass of the populati<strong>on</strong>, eiders and gulls respectively<br />

dominate the seabirds breeding in the shallow, inland Baltic Sea and its approaches (<strong>ICES</strong> III). Approximately 45% of<br />

all the <strong>ICES</strong> eiders (ca. 1 milli<strong>on</strong> pairs) breed in subarea III. Eiders also reach their largest proporti<strong>on</strong>s (10% and 15%<br />

by number and 19% and 27% by biomass in the inshore NAFO subareas 4 (St. Lawrence and Nova Scotia) and 5 (Gulf<br />

of Maine and Georges Bank) respectively. In these same subareas gulls c<strong>on</strong>stitute ca. 40% by number and 25–45% by<br />

biomass.<br />

The <strong>on</strong>ly subarea in the NAFO and <strong>ICES</strong> areas where gulls dominate the seabird breeding community is NAFO 6 (south<br />

Maine to Virginia). Of nearly 250 000 pairs of seabirds breeding in this subarea, 70% are gulls (mainly laughing gulls<br />

and herring gulls). They and terns make up nearly the entire community (88% and 8% of the total biomass). In the<br />

groupings of <strong>ICES</strong> subareas used in this report, gulls make up 6–40% of the numbers and 6–36% of the biomass.<br />

Nowhere do terns c<strong>on</strong>stitute > 10% of the numbers or 1% of the biomass.<br />

In additi<strong>on</strong> to the large differences in breeding populati<strong>on</strong>s in the W and E Atlantic, there are much larger differences<br />

between the two regi<strong>on</strong>s due to huge seas<strong>on</strong>al movements of birds from the Southern Atlantic through NAFO areas than<br />

through <strong>ICES</strong> areas. These, and large seas<strong>on</strong>al migratory movements of birds between and within <strong>ICES</strong> and NAFO<br />

areas are described and discussed in the next secti<strong>on</strong>.<br />

5.2.2 Seas<strong>on</strong>al changes in numbers and biomass of seabirds in <strong>ICES</strong> and NAFO areas<br />

In general, the seabird community in the NAFO areas is dominated by huge numbers of individuals feeding at low<br />

trophic levels, two of which are of small-sized planktivorous species (Wils<strong>on</strong>’s storm petrel, little auk).<br />

Due to temporary movements of birds from the southern Atlantic into northern waters, and the migrati<strong>on</strong> of North<br />

Atlantic seabirds across fishing areas, there are c<strong>on</strong>siderable seas<strong>on</strong>al changes in numbers and biomasses of seabirds<br />

occupying the various parts of the North Atlantic (Tables 5.3–5.6). Such movements include those of large numbers of<br />

birds out of the northernmost subareas (<strong>ICES</strong> I and IIb, NAFO 0 and 1) into milder subareas in autumn and winter. For<br />

example, the large increase in NAFO 2 and 3 (E. Newfoundland and Labrador) in autumn and winter is due to milli<strong>on</strong>s<br />

of eiders, auks and kittiwakes entering the areas from col<strong>on</strong>ies outside the NAFO areas (in the eastern Canadian Arctic),<br />

col<strong>on</strong>ies in NAFO 0 and 1 (E. Baffin Island and W. Greenland) and in <strong>ICES</strong> IIa, IIb and Va (Barents Sea, Norwegian<br />

Sea and Iceland). Similarly, nearly seven milli<strong>on</strong> seaducks winter in the Baltic Sea (<strong>ICES</strong> IIIa-d) but leave again in<br />

spring to breed inland. These include 4.3 milli<strong>on</strong> l<strong>on</strong>g-tailed ducks, 1.2 milli<strong>on</strong> comm<strong>on</strong> scoters and 1 milli<strong>on</strong> velvet<br />

scoters. In the western Atlantic, 4.5–5 milli<strong>on</strong> n<strong>on</strong>-breeding birds (mostly great shearwaters, sooty shearwaters,<br />

Wils<strong>on</strong>’s storm-petrels) enter the southern NAFO areas from the southern oceans in summer, and 1.5 milli<strong>on</strong> ring-billed<br />

gulls move out to the coast in the same areas in winter (Table 5.7, <strong>ICES</strong> 2003).<br />

It should be noted, however, that the quantificati<strong>on</strong> of the movements of seabirds across the fishing areas is based <strong>on</strong><br />

very poor data as very little is known about the actual numbers of the different species in the different areas at a given<br />

time. Many of the figures used here are not more than educated guesses!<br />

Table 5.3. Approximate numbers of seabirds (milli<strong>on</strong>s of individuals) occupying <strong>ICES</strong> subareas in winter, spring, summer, and<br />

autumn.<br />

<strong>ICES</strong> subarea Winter Spring Summer Autumn<br />

I,IIa,IIb Barents and Norwegian Seas 15.1 22.8 26.8 27.3<br />

Va,XIVa,b E. Greenland and Iceland 21.4 33.9 38.6 33.1<br />

IVa-c,VIId,e North Sea and English Channel 8.9 8.3 8.8 8.8<br />

IIIa-d Baltic, Skagerrak and Kattegat 10.2 9.8 3.9 5.8<br />

Vb,VIa,b,f,g,j Faeroes and W. UK 10.3 12.6 13.2 13.6<br />

VIIIa-c,IXa,X France, Iberia, Azores 1.3 2.1 1.0 1.4<br />

Total 67.1 89.5 92.4 90.1<br />

22<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Table 5.4. Approximate numbers of seabirds (milli<strong>on</strong>s of individuals) occupying NAFO areas in winter, spring, summer, and autumn.<br />

NAFO areas Winter Spring Summer Autumn<br />

0 Eastern Baffin Island 0 4.6 4.6 3.8<br />

1 West Greenland 19.6 117.6 115.6 19.6<br />

2 and 3 East NFL and Labrador 110.9 23.8 21.2 128.7<br />

4 Gulf of St. Lawrence and Scotian Shelf 2.0 3.7 4.4 4.3<br />

5 Gulf of Maine 0.9 18.9 3.5 10.0<br />

6 L<strong>on</strong>g Island to Cap Hatteras 2.6 3.6 3.6 6.0<br />

Total 136.0 172.2 152.9 172.3<br />

The total biomass of seabirds occupying <strong>ICES</strong> subareas (Table 5.5) in different seas<strong>on</strong>s varies between 54,000 t<strong>on</strong>nes<br />

(winter) to 64 000 t<strong>on</strong>nes (spring), whereas the total biomass of seabirds occupying NAFO subareas (Table 5.6) in<br />

different seas<strong>on</strong>s is even more variable, ranging from 34 000 t<strong>on</strong>nes (winter) to 46 000 t<strong>on</strong>nes (spring and autumn).<br />

Note, however, that the numbers (and biomass) figures are based <strong>on</strong> the maximum number of a given species in any<br />

given seas<strong>on</strong> <strong>on</strong>ly, and do not c<strong>on</strong>sider their length of stay within the given seas<strong>on</strong>. Short stays in two or more areas will<br />

thus be reflected in the total numbers and biomasses in those areas, e.g., in the migrati<strong>on</strong> seas<strong>on</strong>s spring, and autumn.<br />

Table 5.5. Approximate biomass (t<strong>on</strong>nes x 1000) of seabirds occupying <strong>ICES</strong> subareas in winter, spring, summer, and autumn.<br />

<strong>ICES</strong> subarea Winter Spring Summer Autumn<br />

I,IIa,IIb Barents and Norwegian Seas 10.5 15.2 17.0 17.0<br />

Va,XIVa,b E. Greenland and Iceland 15.3 20.3 20.6 19.9<br />

IVa-c,VIId,e North Sea and English Channel 7.1 6.8 6.9 7.0<br />

IIIa-d Baltic, Skagerrak and Kattegat 11.2 11.1 5.1 7.0<br />

Vb,VIa,b,f,g,j Faeroes and W. UK 7.6 9.3 9.5 9.5<br />

VIIIa-c,IXa,X France, Iberia, Azores 2.2 1.3 0.9 0.9<br />

Total 53.9 64.0 60.0 61.4<br />

Table 5.6. Approximate biomass of seabirds (t<strong>on</strong>nes x 1000) in NAFO occupying NAFO areas in winter, spring, summer, and<br />

autumn.<br />

NAFO areas Winter Spring Summer Autumn<br />

0 Eastern Baffin Island 0 4.7 4.7 3.4<br />

1 West Greenland 8.1 23.2 20.8 8.1<br />

2 and 3 East NFL and Labrador 21.7 8.1 5.7 23.9<br />

4 Gulf of St. Lawrence and Scotian Shelf 1.6 3.7 3.1 3.5<br />

5 Gulf of Maine 1.0 4.2 2.7 3.4<br />

6 L<strong>on</strong>g Island to Cap Hatteras 1.6 2.4 2.4 3.7<br />

Total 34.1 46.4 39.5 46.0<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 23


Table 5.7. Approximate numbers (individuals x 1000) and biomass (t<strong>on</strong>nes) of birds that breed outside NAFO subareas but enter<br />

NAFO 5 and 6 (from <strong>ICES</strong>. 2003, Table 3.4).<br />

Species Number Biomass<br />

Greater shearwater 1900 2100<br />

Sooty shearwater 410 320<br />

Wils<strong>on</strong>’s storm-petrel 600 20<br />

L<strong>on</strong>g-tailed duck 230 190<br />

Black scoter 60 60<br />

Surf scoter 120 150<br />

Velvet scoter 100 130<br />

Red-breasted merganser 60 40<br />

Red-necked phalarope 250 10<br />

Grey phalarope 240 10<br />

B<strong>on</strong>aparte’s gull 60 10<br />

Ring-billed gull 1500 600<br />

Total 5530 3640<br />

5.2.3 C<strong>on</strong>sumpti<strong>on</strong> estimates<br />

<strong>Seabird</strong>s occupying the NAFO and <strong>ICES</strong> areas of the North Atlantic c<strong>on</strong>sume an estimated 11.5 milli<strong>on</strong> t<strong>on</strong>nes of food<br />

per year with 45% being taken in the western sector and 55% in the east. This total is ca. 10–20% of the total<br />

c<strong>on</strong>sumpti<strong>on</strong> by the world’s seabirds (max. CI range = 56–133 milli<strong>on</strong> t<strong>on</strong>nes) estimated by Brooke (2003). Although<br />

this percentage seems relatively high, it may reflect both the elevated c<strong>on</strong>sumpti<strong>on</strong> by seabirds at high latitudes and the<br />

c<strong>on</strong>servative approach of Brooke’s estimate.<br />

The near equality of the overall c<strong>on</strong>sumpti<strong>on</strong> <strong>on</strong> both sides of the Atlantic is despite the fact that nearly twice the<br />

number of seabirds occupies the NAFO areas and is a reflecti<strong>on</strong> of the huge numbers of small species in the west.<br />

The total food c<strong>on</strong>sumpti<strong>on</strong> estimates for both the <strong>ICES</strong> subareas and for the NAFO subareas peak in the summer<br />

seas<strong>on</strong> at levels 44% and 54% higher than the respective winter c<strong>on</strong>sumpti<strong>on</strong> estimates. The elevated energy demand in<br />

summer is primarily caused by increased reproducti<strong>on</strong> activity, but also the larger numbers of birds (and hence higher<br />

biomass) in summer <strong>on</strong> both sides of the Atlantic. In the <strong>ICES</strong> area there are 37% more birds (and an 11% higher<br />

biomass) and in the NAFO area 12% more birds (and 16% higher biomass) in summer than in winter. In the NAFO area<br />

the extra food c<strong>on</strong>sumpti<strong>on</strong> caused by reproducti<strong>on</strong> and the summer visitors from the southern hemisphere outweigh by<br />

far the extra c<strong>on</strong>sumpti<strong>on</strong> by wintering visitors entering the NAFO area from the <strong>ICES</strong> area and the eastern Canadian<br />

Arctic (guillemots and seaducks) and leaving the NAFO area for the summer.<br />

Note that while numbers and biomass of seabirds in a given area in a given seas<strong>on</strong> are based <strong>on</strong> maximum numbers in<br />

that seas<strong>on</strong>, the food c<strong>on</strong>sumpti<strong>on</strong> of seabirds occupying the <strong>ICES</strong> subareas (Table 5.8) and the NAFO subareas (Table<br />

5.9) are calculated based <strong>on</strong> the number of days each species stays in a given subarea and thus do not directly<br />

corresp<strong>on</strong>d to the biomass in Tables 5.5 and 5.6.<br />

24<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Table 5.8. Approximate food c<strong>on</strong>sumpti<strong>on</strong> (t<strong>on</strong>nes x 1000) by seabirds occupying <strong>ICES</strong> subareas in winter, spring, summer, and<br />

autumn.<br />

<strong>ICES</strong> subarea Winter Spring Summer Autumn Total<br />

I,IIa,IIb Barents and Norwegian Seas 270 360 570 450 1650<br />

Va,XIVa,b E. Greenland and Iceland 380 470 690 530 2080<br />

IVa-c,VIId,e North Sea and English Channel 180 170 220 180 750<br />

IIIa-d Baltic, Skagerrak and Kattegat 270 250 140 160 810<br />

Vb,VIa,b,f,g,j Faeroes and W. UK 190 220 290 240 950<br />

VIIIa-c,IXa,X France, Iberia, Azores 40 20 30 20 110<br />

Total 1340 1490 1940 1580 6350<br />

Table 5.9. Approximate food c<strong>on</strong>sumpti<strong>on</strong> (t<strong>on</strong>nes x 1000) by seabirds occupying NAFO areas in winter, spring, summer, and<br />

autumn.<br />

NAFO areas Winter Spring Summer Autumn Total<br />

0 Eastern Baffin Island 0 100 130 60 300<br />

1 West Greenland 230 670 1110 230 2240<br />

2 and 3 East NFL and Labrador 730 230 180 800 1940<br />

4 Gulf of St. Lawrence and Scotian Shelf 50 70 80 60 250<br />

5 Gulf of Maine 20 75 100 40 230<br />

6 L<strong>on</strong>g Island to Cap Hatteras 40 50 60 60 200<br />

Total 1070 1190 1650 1260 5160<br />

5.2.4 Comparis<strong>on</strong> to earlier models<br />

Seas<strong>on</strong>al movements. Taking seas<strong>on</strong>al movements of birds between NAFO and <strong>ICES</strong> areas into account increased the<br />

original estimate of food c<strong>on</strong>sumpti<strong>on</strong> in the <strong>ICES</strong> areas (<strong>ICES</strong> 2002) by 17% (from 5.4 to 6.3 mill. t<strong>on</strong>nes) and in the<br />

NAFO areas by 75% (from 2.9 to 5.2 mill. t<strong>on</strong>nes) (Table 5.10). In the <strong>ICES</strong> areas this is most evident in <strong>ICES</strong> IIIa-d<br />

(Baltic, Skagerrak and Kattegat) where taking into account the populati<strong>on</strong> of wintering seaducks doubled the annual<br />

c<strong>on</strong>sumpti<strong>on</strong> estimate for that subarea. The most striking differences in the NAFO areas are due to the huge seas<strong>on</strong>al<br />

influxes of birds from the southern oceans (into NAFO 5 and 6), northern <strong>ICES</strong> areas and the eastern Canadian Arctic<br />

(into NAFO 2 and 3) menti<strong>on</strong>ed above.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 25


Table 5.10 Estimates of food c<strong>on</strong>sumpti<strong>on</strong> (t<strong>on</strong>nes x 1000) by seabirds in <strong>ICES</strong> and NAFO subareas when not c<strong>on</strong>sidering seas<strong>on</strong>al<br />

movements of birds into, out of and through the subareas (a) and when doing so (b).<br />

<strong>ICES</strong> subareas<br />

I,IIa,IIb Barents and Norwegian Seas 1520 1650<br />

Va,XIVa,b E. Greenland and Iceland 1800 2080<br />

IVa-c,VIId,e North Sea and English Channel 690 750<br />

IIIa-d Baltic, Skagerrak and Kattegat 410 810<br />

Vb,VIa,b,f,g,j Faeroes and W. UK 870 950<br />

VIIIa-c,IXa,X France, Iberia, Azores 80 110<br />

Total <strong>ICES</strong> 5420 6 350<br />

NAFO subareas<br />

0 Eastern Baffin Island 220 300<br />

1 West Greenland 1650 2240<br />

2 and 3 East NFL and Labrador 700 1940<br />

4 Gulf of St. Lawrence and Scotian Shelf 180 250<br />

5 Gulf of Maine 100 230<br />

6 L<strong>on</strong>g Island to Cap Hatteras 50 200<br />

Total NAFO 2910 5160<br />

5.3 References<br />

Anker-Nilssen, T., Bakken, V., Strøm, H., Golovkin, A., Bianki, V.V., and Tatarinkova, I. (eds.) 2000. The status of<br />

marine birds breeding in the Barents Sea regi<strong>on</strong>. Norsk Polarinst. Rapportserie No. 113, Tromsø. 213 pp.<br />

Bakken, V., Runde, O., and Tjørve, E. 2003. Norsk ringmerkingsatlas. Vol. 1. Stavanger Museum, Stavanger. 431 pp.<br />

Barrett, R.T., Anker-Nilssen, T., Gabrielsen, G.W., and Chapdelaine, G. 2002. Food c<strong>on</strong>sumpti<strong>on</strong> by seabirds in<br />

Norwegian waters. <strong>ICES</strong> Journal of Marine Science, 59: 43–57.<br />

Birt-Friesen, V.L., M<strong>on</strong>tevecchi, W.A., Cairns, D.K., and Macko, S.A. 1989. Activity specific metabolic rates of freeliving<br />

northern gannets and other seabirds. <strong>Ecology</strong>, 70: 357–367.<br />

Brooke, M. de L. 2003. The food c<strong>on</strong>sumpti<strong>on</strong> of the world’s seabirds. Proceedings of the Royal Society of L<strong>on</strong>d<strong>on</strong>.<br />

Series B: Biological Sciences. Biology Letters, 271(S4): 246-248.<br />

Cairns, D.K., Chapdelaine, G., and M<strong>on</strong>tevecchi, W.A. 1991. Prey exploitati<strong>on</strong> by seabirds in the Gulf of St. Lawrence.<br />

Canadian Special Publicati<strong>on</strong>s Fisheries Aquatic Sciences, 113: 277–291.<br />

Cramp, S. (ed.) 1985. The birds of the Western Palearctic, Vol IV. Oxford University Press. 960 pp.<br />

Cramp, S. and Simm<strong>on</strong>s, K.E.L. (ed.) 1977. The birds of the Western Palearctic, Vol I. Oxford University Press. 722<br />

pp.<br />

Cramp, S. and Simm<strong>on</strong>s, K.E.L. (ed.) 1983. The birds of the Western Palearctic, Vol III. Oxford University Press. 913<br />

pp.<br />

Delany, S., and Scott, D. (eds.) 2002. Waterbird populati<strong>on</strong> estimates – third ed. Wetlands Internati<strong>on</strong>al Global ser. No.<br />

12, Wageningen, Netherlands. 226 pp.<br />

Diam<strong>on</strong>d, A.W., Gast<strong>on</strong>, A.J., and Brown, R.G.B. 1993. Studies of high-latitude seabirds. 3. A model of the energy<br />

demands of the seabirds of eastern and Arctic Canada. CWS Occasi<strong>on</strong>al Papers, 77: 1–39.<br />

Durinck, J., Skov, H., Jensen, F.P., and Pihl, S. 1994. Important marine areas for wintering birds in the Baltic Sea. EU<br />

DG XI research c<strong>on</strong>tract no. 2242/90–09–01. Ornis C<strong>on</strong>sult report 1994, 110 pp.<br />

Ellis, H.I., and Gabrielsen, G.W. 2002. Energetics of free-ranging seabirds. In Biology of marine birds. Ed. by<br />

Schreiber, E.A. and Burger, J. CRC Press, Boca Rat<strong>on</strong>, Florida: 359–407.<br />

Gabrielsen, G.W. 1994. Energy expenditure in arctic seabirds. D. Phil. thesis, Univ. Tromsø, Norway.<br />

Gales, R.P., and Green, B. 1990. The annual energetics cycle of little penguins Eudyptula minor. <strong>Ecology</strong>, 71: 2297–<br />

2312.<br />

Hagemeijer, W.J.M., and Blair, M.J. (eds.). 1997. The EBCC atlas of European breeding birds. Poyser, L<strong>on</strong>d<strong>on</strong>. 903 pp.<br />

<strong>ICES</strong> 2002. Report of the working group <strong>on</strong> seabird ecology. <strong>ICES</strong> <strong>CM</strong> 2002/C:04.<br />

<strong>ICES</strong> 2003. Report of the working group <strong>on</strong> seabird ecology. <strong>ICES</strong> <strong>CM</strong> 2003/C:03.<br />

26<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong><br />

Total<br />

a<br />

Total<br />

b


Kershaw, M., and Cranswick, P.A. 2003. Numbers of wintering waterbirds in Great Britain, 1994/1995–1998/1999: I.<br />

Waterfowl and selected waterbirds. Biological C<strong>on</strong>servati<strong>on</strong>, 111: 91–104.<br />

Lyngs, P. 2003. Migrati<strong>on</strong> and winter ranges of birds in Greenland. Dansk Ornitologisk Forenings Tidsskrift, 97: 1–<br />

165.<br />

Merkel, F. R., Mosbech, A., Boertmann, D. M., and Grøndahl, L. 2002. Winter seabird distributi<strong>on</strong> and abundance off<br />

southwest Greenland, 1999. Polar Research, 21:17–36.<br />

Mosbech, A.., and Boertmann, D. 1999. Distributi<strong>on</strong>, abundance and reacti<strong>on</strong> to aerial surveys of post-breeding king<br />

eiders (Somateria spectabilis) in western Greenland. Arctic, 52: 188–203.<br />

Nagy, K.A., Ginard, I.A., and Brown, T.K. 1999. Energetics of free-ranging mammals, reptiles and birds. Annual<br />

Reviews Nutriti<strong>on</strong>, 19: 247–277.<br />

Nygård, T., Larsen, B.H., Follestad, A., and Strann, K.-B. 1988. Numbers and distributi<strong>on</strong> of wintering waterfowl in<br />

Norway. Wildfowl, 39: 164–176.<br />

Petersen, A. 1982. [Icelandic seabirds]. In Fuglar. Ed. By Gardarss<strong>on</strong>, A. Rit Landverndar, 8. 216 pp.<br />

Wernham, C.V., Toms, M.P., Marchant, J.H., Clark, J.A., Siriwardena, G.M., and Baillie, S.R. (eds.). 2002. The<br />

Migrati<strong>on</strong> Atlas: movements of the birds of Britain and Ireland. Poyser, L<strong>on</strong>d<strong>on</strong>. 884 pp.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 27


Appendix 5.1. An example of the c<strong>on</strong>sumpti<strong>on</strong> model input data for breeding populati<strong>on</strong>s (body mass, length of breeding seas<strong>on</strong>,<br />

field metabolic rate (FMR, outside the breeding seas<strong>on</strong> and during the breeding seas<strong>on</strong>). This example is from <strong>ICES</strong> Va (Iceland).<br />

Note that body mass (and hence FMR) will vary geographically. This is accounted for in the different areas.<br />

Body<br />

mass<br />

g<br />

Breeding<br />

populati<strong>on</strong> 1<br />

pairs<br />

Total no.<br />

of indivs.<br />

Period<br />

present<br />

in<br />

area<br />

Length<br />

of<br />

breeding<br />

seas<strong>on</strong><br />

d<br />

FMR<br />

outside<br />

breeding<br />

seas<strong>on</strong><br />

kj/d<br />

FMR<br />

during<br />

breeding<br />

Northern fulmar 810 1500000 5100000 Jan-Dec 120 814 1016<br />

Manx shearwater 450 8500 28900 Mar-Oct 150 538 715<br />

Leach's petrel 50 115000 391000 Mar-Oct 150 114 192<br />

Storm petrel 25 75000 255000 Mar-Oct 150 70 127<br />

Northern gannet 3200 25000 85000 Mar-Oct 150 2709 4048<br />

Great cormorant 2500 3150 11340 Mar-Oct 100 2254 3383<br />

Shag 1800 6600 23760 Mar-Oct 100 1764 2664<br />

Comm<strong>on</strong> eider 2200 300000 1080000 Jan-Dec 50 2049 3083<br />

Great skua 1400 5400 19440 Apr-Sep 100 1462 2219<br />

Arctic skua 350 7500 27000 May-Sep 80 520 810<br />

Black-headed gull 250 27500 99000 Apr-Sep 80 404 634<br />

Mew gull 380 550 1980 Apr-Sep 80 553 860<br />

Herring gull 1000 7500 27000 Mar-Oct 90 1138 1738<br />

Lesser black-backed gull 800 30000 108000 Apr-Sep 90 963 1478<br />

Great black-backed gull 1650 17500 63000 Mar-Oct 100 1653 2501<br />

Glaucous gull 1800 12500 45000 Apr-Sep 100 1764 2664<br />

Black-legged kittiwake 400 631000 2271600 Mar-Oct 90 574 893<br />

Arctic tern 110 250000 900000 May-Aug 70 219 349<br />

Comm<strong>on</strong> guillemot 1000 990000 3366000 Feb-Nov 70 1138 1738<br />

Brünnich's guillemot 950 580000 1972000 Feb-Nov 70 1095 1674<br />

Razorbill 700 380000 1292000 Mar-Oct 70 872 1341<br />

Black guillemot 400 15000 54000 Jan-Dec 90 574 893<br />

Atlantic puffin 450 2760000 9384000 Mar-Oct 110 627 972<br />

1 References<br />

seas<strong>on</strong><br />

Gardarss<strong>on</strong>, A. 1995. Numbers and distributi<strong>on</strong> of comm<strong>on</strong> murre Uria aalge, thick-billed murre U. lomvia and<br />

razorbill Alca torda in Iceland. Bliki, 16: 47–65.<br />

Gardarss<strong>on</strong>, A. 1996a. Numbers and distributi<strong>on</strong> of breeding kittiwake Rissa tridactyla in Iceland. Bliki, 17: 1–16.<br />

Gardarss<strong>on</strong> A. 1996b. Numbers of breeding cormorants Phalacrocorax carbo in Iceland in 1975–1994. Bliki, 17: 35–<br />

42.<br />

Gardarss<strong>on</strong> A. 1979. A census of breeding cormorants (Phalacrocorax carbo) and shags (Phalacrocorax aristotelis) in<br />

Iceland in 1975. Natturufraedingurinn, 49:126–154.<br />

Gudmundss<strong>on</strong> G.A. 1998. The importance of wetlands for birds. (Þýðing votlendis fyrir fugla). In Icelandic wetlands;<br />

protecti<strong>on</strong> and exploitati<strong>on</strong>. (Íslensk votlendi; verndun og nýting. Ed. by Olafss<strong>on</strong>, J.S. Haskolautgafan,<br />

Reykjavik: 167-172.<br />

Gardarss<strong>on</strong> A. Pers<strong>on</strong>al communicati<strong>on</strong>.<br />

Icelandic Institute of Natural History 2000. Red list of threatened species in Iceland 2, birds.<br />

Lund-Hansen, L.C. and P. Lange 1991. The numbers and distributi<strong>on</strong> of Great Skua Stercorarius skua breeding in<br />

Iceland 1984–1985. Acta Naturalia Islandica 34, 16pp.<br />

28<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong><br />

kj/d


6 CONSUMPTION OF PREY BY SEABIRDS IN THE NORTH SEA AS INPUT FOR THE STUDY<br />

GROUP ON MULTISPECIES ASSESSMENTS IN THE NORTH SEA (SGMSNS)<br />

Term of Reference: provide the Study <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> Multispecies Assessments in the North Sea (SGMSNS) with data <strong>on</strong><br />

the c<strong>on</strong>sumpti<strong>on</strong> of different prey by seabirds in the North Sea, in a format specified by SGMSNS.<br />

In resp<strong>on</strong>se to a request from SGMSNS in 2003, the <strong>WGSE</strong> c<strong>on</strong>sidered in March 2003 whether seabird c<strong>on</strong>sumpti<strong>on</strong> of<br />

prey in the North Sea could be presented in a form suitable for incorporati<strong>on</strong> into an MSVPA model. That meeting<br />

c<strong>on</strong>cluded that there would be c<strong>on</strong>siderable work required to achieve such an aim, and certain assumpti<strong>on</strong>s and<br />

simplificati<strong>on</strong>s would be necessary, but that such work would be possible providing the form of the data requirement of<br />

SGMSNS could be clearly specified. Our Term of Reference f) required <strong>WGSE</strong> to prepare data <strong>on</strong> the c<strong>on</strong>sumpti<strong>on</strong> of<br />

different prey by seabirds in the North Sea, in a format specified by SGMSNS. Unfortunately, <strong>WGSE</strong> received no<br />

guidance from SGMSNS prior to our meeting in Aberdeen, <strong>on</strong> the format in which data should be provided for input to<br />

Multispecies Assessments in the North Sea and <strong>on</strong>ly rather limited informati<strong>on</strong> while we were meeting in Aberdeen.<br />

We were advised, however, that this Term of Reference had been superseded by the funding of an EC c<strong>on</strong>tract<br />

‘BECAUSE’ which will be carrying out essentially this same work, and therefore that this Term of Reference should<br />

perhaps no l<strong>on</strong>ger be included in our work programme. Although we tried to obtain c<strong>on</strong>firmati<strong>on</strong> of this fact from the<br />

Chair of SGMSNS and from <strong>ICES</strong>, we were unable to get any clear resp<strong>on</strong>se <strong>on</strong> this point. We therefore assumed that<br />

this Term of Reference should be left until clarificati<strong>on</strong> of the situati<strong>on</strong> could be obtained. <strong>WGSE</strong> would be happy to<br />

work <strong>on</strong> this tor intersessi<strong>on</strong>ally if the decisi<strong>on</strong> we made in Aberdeen was based <strong>on</strong> incorrect advice.<br />

7 ECOLOGICAL QUALITY OBJECTIVES<br />

Term of Reference: rec<strong>on</strong>sider the formulati<strong>on</strong> of the EcoQOs listed below, determine whether a more specific EcoQO<br />

is needed in terms of its specificati<strong>on</strong> to the metric, time and geographical area, and as necessary propose more specific<br />

EcoQO(s) [OSPAR <strong>2004</strong>/1]:<br />

i) EcoQ element (f) Proporti<strong>on</strong> of oiled comm<strong>on</strong> guillemots am<strong>on</strong>g those found dead or dying <strong>on</strong> beaches,<br />

ii) EcoQ element (g) Mercury c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs and feathers,<br />

iii) EcoQ element (h) Organochlorine c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs,<br />

iv) EcoQ element (i) Plastic particles in stomachs of seabirds,<br />

v) EcoQ element (j) Local sandeel availability to black-legged kittiwakes,<br />

vi) EcoQ element (k) <strong>Seabird</strong> populati<strong>on</strong> trends as an index of seabird community health.<br />

7.1 Introducti<strong>on</strong><br />

The Fifth North Sea C<strong>on</strong>ference in 2002 agreed that six Ecological Quality Elements relating to seabirds in the North<br />

Sea would be further developed. These elements were:<br />

• 4(f) Proporti<strong>on</strong> of oiled comm<strong>on</strong> guillemots am<strong>on</strong>g those found dead or dying <strong>on</strong> beaches,<br />

• 4(g) Mercury c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs and feathers,<br />

• 4(h) Organochlorine c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs,<br />

• 4(i) Plastic particles in stomachs of seabirds,<br />

• 4(j) Local sandeel availability to black-legged kittiwakes,<br />

• 4(k) <strong>Seabird</strong> populati<strong>on</strong> trends as an index of seabird community health.<br />

An Ecological Quality Objective was agreed for the first of these Elements:<br />

‘The proporti<strong>on</strong> of [oiled comm<strong>on</strong> guillemots] should be 10% or less of the total found dead or dying in all areas of the<br />

North Sea’<br />

Within the OSPAR framework, The Netherlands agreed to act as a lead country for Element 4(f) <strong>on</strong> oiled comm<strong>on</strong><br />

guillemots and the UK for Element 4(j) <strong>on</strong> sandeels and kittiwakes. Progress made in the development of these EcoQ<br />

Elements was reported to OSPAR’s Biodiversity Committee in early <strong>2004</strong> (OSPAR <strong>2004</strong>a, b). This Committee agreed a<br />

number of points about these Ecological Quality Elements that are reflected in the c<strong>on</strong>siderati<strong>on</strong>s below.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 29


<strong>WGSE</strong> has resp<strong>on</strong>ded over the last few years to several terms of reference relating to Ecological Quality Objectives. In<br />

resp<strong>on</strong>ding this year, we have tried where possible to avoid repeating the resp<strong>on</strong>ses of previous years. We note that<br />

some papers produced, for example in the c<strong>on</strong>text of OSPAR, do not appear to have taken account of all of our reports<br />

(or even those of <strong>ICES</strong> ACE). We urge those using our resp<strong>on</strong>ses to read those previous resp<strong>on</strong>ses al<strong>on</strong>gside this year’s<br />

work.<br />

7.2 Proporti<strong>on</strong> of oiled comm<strong>on</strong> guillemots am<strong>on</strong>g those found dead or dying <strong>on</strong> beaches<br />

This is the <strong>on</strong>ly seabird EcoQ Element for which an EcoQO has been set for the North Sea pilot project. However, this<br />

EcoQO is c<strong>on</strong>cerned with driving and m<strong>on</strong>itoring the reducti<strong>on</strong> of oil polluti<strong>on</strong> in the North Sea rather than ensuring<br />

that comm<strong>on</strong> guillemot Uria aalge populati<strong>on</strong>s are safeguarded. However, there is no doubt that reducing oil polluti<strong>on</strong><br />

would reduce anthropogenic mortality of comm<strong>on</strong> guillemots and of all other biota adversely affected by oil polluti<strong>on</strong>.<br />

In this c<strong>on</strong>text it should be noted that the 10% objective for the Ecological Quality Element was initially suggested by<br />

<strong>WGSE</strong> as a pragmatic target – accepting that the “no-human effect” level would be 0%, but acknowledging that this<br />

zero level would presently be an unrealistic target, based <strong>on</strong> experience of oil spill reducti<strong>on</strong> efforts around Orkney and<br />

Shetland.<br />

OSPAR (<strong>2004</strong>b) describes progress with this pilot project. The provisi<strong>on</strong> of a manual for volunteers to use when<br />

collecting informati<strong>on</strong> <strong>on</strong> the proporti<strong>on</strong> of oiled birds has ensured standardisati<strong>on</strong> of this aspect. An internati<strong>on</strong>al data<br />

collati<strong>on</strong> system is in place. Two aspects not explicitly addressed in the wording of the EcoQO (but included in<br />

previous background advice) relate to regi<strong>on</strong>al divisi<strong>on</strong>s in the North Sea and frequency of surveys. A “grand total”<br />

percentage of oiled birds would not be appropriate as they may be biased by disproporti<strong>on</strong>ately sized samples in some<br />

areas. In additi<strong>on</strong>, knowledge of the locati<strong>on</strong> of high (or low) proporti<strong>on</strong>s of oiled birds may help to better target any<br />

management or mitigati<strong>on</strong> measures. Based <strong>on</strong> historical precedent, and therefore practicality, <strong>ICES</strong> (2003a) and<br />

OSPAR (<strong>2004</strong>b) suggested a set of fifteen coastal secti<strong>on</strong>s of the North Sea (Table 7.1). Equally, previous advice has<br />

suggested that m<strong>on</strong>thly samples be taken in each secti<strong>on</strong> for the winter m<strong>on</strong>ths between November and April in each<br />

year. Any lower sampling rates carry the risk that external factors could severely bias the result and that variance<br />

around the mean oiling rate would be higher than ideal. <strong>WGSE</strong> notes that surveys for oiled guillemots are not yet<br />

occurring <strong>on</strong> all of these coastal secti<strong>on</strong>s or at these times.<br />

Table 7.1. Suggested coastal secti<strong>on</strong>s for recording and reporting of proporti<strong>on</strong>s of oiled comm<strong>on</strong> guillemots (after OSPAR <strong>2004</strong>b).<br />

Secti<strong>on</strong> Boundaries Country<br />

1 Shetland UK<br />

2 Orkney Orkney and north coast of Scotland UK<br />

3 East Scotland Duncansby Head to Berwick <strong>on</strong> Tweed UK<br />

4 Northeast England Berwick <strong>on</strong> Tweed to Spurn Head UK<br />

5 East England Spurn Head to North Foreland UK<br />

6 Eastern Channel Line between North Foreland and Belgian/French border to line from<br />

Cherbourg to Portland<br />

UK, F<br />

7 Western Channel Line between Cherbourg and Portland to line from Lizard to Ouessant UK, F<br />

8 Eastern Southern Bight Belgian/French border to Texel B, NL<br />

9 Southern German Bight North Sea coast Frisian Islands Texel to Elbe NL, FRG<br />

10 Western Wadden Sea Mainland and Wadden Sea coast Frisian Islands Texel to Elbe NL, FRG<br />

11 Eastern Wadden Sea Mainland coast and Wadden Sea coast Elbe to Esbjerg FRG, DK<br />

12 Eastern German Bight North Sea coast Wadden Sea Islands Elbe to Fanø FRG, DK<br />

13 Danish west coast Mainland coast Esbjerg – Hanstholm DK<br />

14 Skagerrak/ Oslofjord East of line between Hanstholm to Kristiansand, north of a line from<br />

Skagen to Gothenburg<br />

15 SW Norway Kristiansand to Stadt N<br />

30<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong><br />

N, DK, S


<strong>WGSE</strong> and ACE recommended in 2003 (<strong>ICES</strong> 2003a, 2003b) that trends might be most easily reported as five-year<br />

running mean percentages oiled. In line with this, <strong>ICES</strong> (2003a) advised that a period of at least five years in which an<br />

average of 10% or less oiled comm<strong>on</strong> guillemots has been recorded should occur before the c<strong>on</strong>clusi<strong>on</strong> that the<br />

objective has been reached could be justified statistically.<br />

<strong>WGSE</strong> therefore suggests that the EcoQO be reformulated as:<br />

The average proporti<strong>on</strong> of oiled comm<strong>on</strong> guillemots should be 10% or less of the total found dead or dying in<br />

each of 15 areas of the North Sea over a period of at least five years. Sampling should occur in all winter m<strong>on</strong>ths<br />

(November to April) of each year.<br />

7.3 Mercury c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs (and feathers)<br />

This EcoQ relates to mercury c<strong>on</strong>centrati<strong>on</strong> (mg/kg) in eggs of comm<strong>on</strong> terns Sterna hirundo and Eurasian<br />

oystercatchers Haematopus ostralegus, two comm<strong>on</strong> and widely distributed species characterised by different foraging<br />

strategies and food chains. In previous years, <strong>WGSE</strong> has suggested that an EcoQO might be established for mercury<br />

c<strong>on</strong>centrati<strong>on</strong>s in a combinati<strong>on</strong> of bird feathers and eggs. Recognising a comment from OSPAR BDC that EcoQOs<br />

ought to focus <strong>on</strong> features that can potentially be influenced by further human management, and recognising the need to<br />

reduce the complexity of the EcoQO system, <strong>WGSE</strong> suggests reducing this EcoQ to focus <strong>on</strong> bird eggs al<strong>on</strong>e (see also<br />

Secti<strong>on</strong> 7.4, below). <strong>Seabird</strong> eggs are already used to m<strong>on</strong>itor mercury <strong>on</strong> southern North Sea coasts as part of the<br />

TMAP project in the Wadden Sea (using JAMP guidelines OSPAR, 1997).<br />

<strong>WGSE</strong> recommends sampling sites near estuaries, important cities or industrial areas in order to cover hot spots of<br />

mercury emissi<strong>on</strong>s and especially of riverine inputs (e.g., Becker et al., 2001). We suggest sampling at sites near the<br />

estuaries of the Rivers Elbe, Weser, Ems, Rhine/Scheld, Thames, Humber, Tees, and Forth. However, with respect to<br />

atmospheric inputs, the northern parts of the North Sea should be covered as reference areas where lower mercury<br />

levels are to be expected compared to the estuaries listed above. We suggest sampling sites in similar (but n<strong>on</strong>industrial)<br />

habitats in southwestern Norway and the Moray Firth. An alternative would be to aim to reduce levels to the<br />

lowest recorded in current m<strong>on</strong>itoring schemes (oystercatcher: 0.1 mg kg −1 ; comm<strong>on</strong> tern 0.2 mg kg −1 , Becker et al.,<br />

2001). Costs (and time) could be saved by combining sampling with EcoQ h) <strong>on</strong> organochlorine c<strong>on</strong>centrati<strong>on</strong>s in<br />

seabird eggs. Sampling should be annual with a sample size of ten eggs (<strong>on</strong>e per nest) per area and species (OSPAR,<br />

1997). Less frequent sampling would increase the period needed to understand if the EcoQO has been met or not.<br />

<strong>WGSE</strong> therefore suggests that the EcoQO be formulated as:<br />

The average c<strong>on</strong>centrati<strong>on</strong>s of mercury in the fresh mass of ten eggs from separate clutches of comm<strong>on</strong> tern and<br />

Eurasian oystercatcher breeding adjacent to the estuaries of the Rivers Elbe, Weser, Ems, Rhine/Scheld,<br />

Thames, Humber, Tees, and Forth should not significantly exceed c<strong>on</strong>centrati<strong>on</strong>s in the fresh mass of ten eggs<br />

from separate clutches of the same species breeding in similar (but not industrial) habitats in southwestern<br />

Norway and in the Moray Firth.<br />

7.4 Organochlorine c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs<br />

<strong>WGSE</strong> reviewed this metric in 2003 (<strong>ICES</strong>, 2003a). <strong>WGSE</strong> did not add to or amend this review in <strong>2004</strong>, but noted that<br />

the OSPAR Biodiversity Committee had commented that it would prefer to have an EcoQ that tracked organochlorines<br />

where further management acti<strong>on</strong> remained to be taken, rather than an EcoQ that tracked the speed at which PCBs and<br />

DDT flushed out of the envir<strong>on</strong>ment (OSPAR <strong>2004</strong>c). <strong>WGSE</strong> noted this, but point out that knowledge of the rate at<br />

which “banned” substances leave biota is of interest and relevance, particularly in ensuring that bans remained<br />

effective.<br />

The objective of this EcoQ is to record any change in ecosystem c<strong>on</strong>taminati<strong>on</strong> with organochlorines by using seabirds<br />

as accumulative indicators. Many organochlorines (PCBs, DDT, chlordanes) have been banned for l<strong>on</strong>g time, but the<br />

str<strong>on</strong>g spatial trends of c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs at the southern North Sea in recent times and local erratic<br />

increases indicate c<strong>on</strong>tinuing inputs into the marine envir<strong>on</strong>ment (e.g., increased levels of PCBs and DDTs at<br />

Julianapolder, Dutch Wadden Sea, and at Elbe estuary; chlordanes at Julianapolder; Becker et al., 2001).<br />

Remobilisati<strong>on</strong> of c<strong>on</strong>taminants from sediments by sea currents or by dredging harbours and dumping of the spoil might<br />

be possible causes for these trends and fluctuati<strong>on</strong>s. Furthermore, currently unpublished data from the Wadden Sea<br />

m<strong>on</strong>itoring project (TMAP) <strong>on</strong> c<strong>on</strong>taminants in bird eggs show significant increases of PCBs, DDTs, and chlordanes in<br />

the western part of the Wadden Sea from 1998 to 2003. Other compounds such as HCB or HCHs, which are in use and<br />

emitted (high levels of HCB at the Dollart, and the Elbe estuary; high levels of HCHs at Julianapolder and the Elbe<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 31


estuary), further dem<strong>on</strong>strate the relevance of this EcoQ and of further m<strong>on</strong>itoring as an early warning system that could<br />

help authorities to take appropriate measures to protect the marine envir<strong>on</strong>ment.<br />

Time series of organochlorine c<strong>on</strong>taminati<strong>on</strong> levels of l<strong>on</strong>ger than 40 years exist for various parts of the North Sea (e.g.,<br />

Alcock et al., 2002),. <strong>Seabird</strong> eggs have been used to m<strong>on</strong>itor organochlorines in parts of the North Sea regi<strong>on</strong> for many<br />

years, e.g., within in the TMAP in the Wadden Sea (Becker et al., 2001). These data have been used in North Sea QSRs<br />

(e.g., Bakker et al., 1999).<br />

<strong>WGSE</strong> suggested in 2003 that practical EcoQOs could be < 20 ng total PCBs g −1 egg fresh mass, < 10 ng DDT and<br />

metabolites g −1 egg fresh mass, < 2 ng HCB g −1 egg fresh mass, < 2 ng HCH g −1 egg fresh mass for eggs of comm<strong>on</strong> tern<br />

and Eurasian oystercatcher from both the southern and the northern North Sea.<br />

<strong>WGSE</strong> suggests further refining the geographic specificity of m<strong>on</strong>itoring (and therefore of the EcoQO) by focusing <strong>on</strong><br />

areas of high riverine input and other hot spots of organochlorine inputs. <strong>WGSE</strong> thus suggests sampling sites should be<br />

chosen adjacent to the Rivers Elbe, Weser, Ems, Rhine/Scheld, Thames, Humber, Tees, and Forth. However, with<br />

respect to the <strong>on</strong>going atmospheric inputs (especially of PCBs), as reference areas also the northern parts of the North<br />

Sea should be covered where lower organochlorine levels are to be expected. We suggest sampling sites in similar (but<br />

n<strong>on</strong>-industrial) habitats in southwestern Norway and the Moray Firth. The comm<strong>on</strong> and widely distributed species<br />

selected offer adequate col<strong>on</strong>y sites for sampling under these requirements (see the TMAP in the Wadden Sea as<br />

example, Becker et al., 2001). Combining sample sites with EcoQ g) <strong>on</strong> mercury c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs (see<br />

Secti<strong>on</strong> 7.3) would save time and cost.<br />

<strong>WGSE</strong> therefore suggests that the EcoQO be formulated as:<br />

For each site, the average c<strong>on</strong>centrati<strong>on</strong>s in fresh mass of the eggs of comm<strong>on</strong> tern and Eurasian oystercatcher of<br />

PCBs should not exceed 20 ng g −1 ; of DDT and metabolites should not exceed 10 ng g −1 ; and of HCB and HCH<br />

should each not exceed 2 ng g −1 . Sampling should be of ten eggs of each species from separate clutches of birds<br />

breeding adjacent to the estuaries of the Rivers Elbe, Weser, Ems, Rhine/Scheld, Thames, Humber, Tees, and<br />

Forth, and in similar (but not industrial) habitats in southwestern Norway and in the Moray Firth.<br />

7.5 Plastic particles in stomachs of seabirds<br />

<strong>WGSE</strong> reviewed this EcoQ in 2002 and 2003 (<strong>ICES</strong>, 2002, 2003a). These reports, and ACE (<strong>ICES</strong>, 2003b), endorsed<br />

the c<strong>on</strong>clusi<strong>on</strong>s of Van Franeker and Meijboom (2002, 2003) that stomach c<strong>on</strong>tents analysis of beach-washed northern<br />

fulmars Fulmarus glacialis offer a reliable m<strong>on</strong>itoring tool for changes in the abundance of plastic litter at sea.<br />

Following these recommendati<strong>on</strong>s, a study running from May 2002 to December <strong>2004</strong> has been established as part of<br />

the EC-funded Save the North Sea project (EU Interreg IIIB J-No 1–16–31–7–502–02) and material is being collected<br />

in seven countries around the North Sea and in adjacent waters 1 . This project should provide further data <strong>on</strong> the<br />

suitability of this EcoQ. With an internati<strong>on</strong>al network of collaborators now (temporarily) in place, and with an agreed<br />

standard methodology now fully operati<strong>on</strong>al, <strong>WGSE</strong> str<strong>on</strong>gly recommends the c<strong>on</strong>tinuati<strong>on</strong> of the work after the<br />

current end of the Save the North Sea programme in December <strong>2004</strong>.<br />

The northern fulmar was chosen over other seabird species due to its well-documented propensity to accumulate plastic<br />

particles in its stomach (Van Franeker, 1985; Moser and Lee, 1992). It is also an abundant species with a “guaranteed”<br />

annual supply of sufficient (some tens to hundreds) of beach-washed corpses in most North Sea countries. No other<br />

species meets both of these c<strong>on</strong>diti<strong>on</strong>s in the North Sea (Save the North Sea project, unpubl. data 2002–2003). An<br />

important further advantage of the northern fulmar is the availability of a data set from the early 1980s, which enables<br />

the development of time-related trends (Van Franeker, 1985).<br />

We c<strong>on</strong>tinue to recommend that the metrics should be the number and mass of plastic particles of each defined type<br />

(“industrial plastic particles”, “user-plastic particles”, and mass of “inert chemical material”) in the stomachs of samples<br />

of 50 to 100 beach-washed northern fulmars collected during winter from areas of the North Sea where such sampling<br />

can be achieved as part of beached-bird surveys. <strong>WGSE</strong> recommended that the proporti<strong>on</strong> of oiled comm<strong>on</strong> guillemots<br />

should be m<strong>on</strong>itored in fifteen secti<strong>on</strong>s of the North Sea coast (see Table 7.1) and c<strong>on</strong>sider it logical that the same<br />

secti<strong>on</strong>s of coast be used to m<strong>on</strong>itor plastic particle c<strong>on</strong>taminati<strong>on</strong>.<br />

1 see http://marine-litter.gpa.unep.org/regi<strong>on</strong>al/Nederland/nl_results.htm<br />

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The present level is that around 60% of northern fulmars in the southern North Sea samples have more than ten plastic<br />

particles in the stomach. In line with previous discussi<strong>on</strong>s, the objective should be to achieve a target of as little plastic<br />

in fulmar stomachs as possible (the “natural level” of this metric should be nil). A value of less than 2% of northern<br />

fulmars having ten or more plastic particles in the stomach seems a reas<strong>on</strong>able and pragmatic choice of target.<br />

With regard to the geographical variati<strong>on</strong> in levels of marine litter, the <strong>WGSE</strong> noted that residence times of plastic in<br />

northern fulmar stomachs are not known, though likely to be at least in the order of many weeks or m<strong>on</strong>ths. These l<strong>on</strong>g<br />

periods achieve an integrati<strong>on</strong> of plastic c<strong>on</strong>taminati<strong>on</strong> over extended periods prior to the death of the birds collected. If<br />

northern fulmars move into the North Sea en masse from less c<strong>on</strong>taminated areas of the North Atlantic, then the<br />

numbers of plastic items may be reduced in samples taken from North Sea beaches where plastic c<strong>on</strong>taminati<strong>on</strong> is<br />

probably higher. Only if northern fulmars tend to remain within <strong>on</strong>e area of the North Sea, they may have levels of<br />

plastic c<strong>on</strong>taminati<strong>on</strong> representative of local polluti<strong>on</strong>. A study of geographical variati<strong>on</strong> in northern fulmar<br />

c<strong>on</strong>taminati<strong>on</strong> around the North Sea is therefore helpful <strong>on</strong>ly in quantifying the spatial pattern of litter distributi<strong>on</strong> if<br />

large influxes of “foreign” birds can be identified. The protocol currently deployed in the Save the North Sea project<br />

includes systematic observati<strong>on</strong>s of colour phase, biometrics, and age from which the geographical origin and age<br />

profile of stranded material may be evaluated. With that, influxes and other anomalies can be identified.<br />

Van Franeker and Meijboom (2002) also recommend that funds should be made available for analysis of the chemical<br />

compositi<strong>on</strong> of the inert “chemical” substances found in a proporti<strong>on</strong> of the northern fulmars. <strong>WGSE</strong> agrees that the<br />

“chemical material” found in many northern fulmar stomachs should receive further analysis to determine its nature,<br />

likely origins, and toxic hazard. Potential technical problems with this specific aspect or any financial implicati<strong>on</strong>s<br />

should not, however, hinder the successful implementati<strong>on</strong> of the EcoQ element (i) where quantities of plastic are the<br />

important parameter to be m<strong>on</strong>itored.<br />

With regard to the oiled seabird EcoQO, <strong>WGSE</strong> and ACE recommended in 2003 (<strong>ICES</strong>, 2003a, 2003b) that trends<br />

might be most easily reported as five-year running mean percentages oiled. In line with this, <strong>ICES</strong> (2003a) advised that<br />

a period of at least five years in which an average of 10% oiled comm<strong>on</strong> guillemots has been recorded should occur<br />

before the c<strong>on</strong>clusi<strong>on</strong> that the objective has been reached could be justified statistically. There are no baseline data <strong>on</strong><br />

the plastic particles in northern fulmars, so we cannot examine annual variability yet. <strong>WGSE</strong> therefore recommend<br />

further investigati<strong>on</strong>s into the amount of variability in plastic loadings between years. For the moment and in line with<br />

the oiled seabirds EcoQO, we suggest a period of five years, over which a value of less than 2% of northern fulmars<br />

having ten or more plastic particles in the stomach in samples of at least 50 corpses should occur before the c<strong>on</strong>clusi<strong>on</strong><br />

that the objective has been reached could be justified statistically.<br />

<strong>WGSE</strong> therefore suggests that the EcoQO be formulated as:<br />

A value of less than 2% of northern fulmars having ten or more plastic particles in the stomach in samples of<br />

50+ beach-washed fulmars found in winter (November to April) from each of fifteen areas of the North Sea over<br />

a period of at least five years.<br />

7.6 Local sandeel availability to black-legged kittiwakes<br />

7.6.1 Objective<br />

The objective of this EcoQ was somewhat misunderstood by OSPAR (<strong>2004</strong>d), who stated that it is “to ensure that<br />

fishing activities do not reduce the supply of food for the breeding black-legged kittiwakes Rissa tridactyla bey<strong>on</strong>d an<br />

acceptable level”. The objective is to use the black-legged kittiwake as an indicator species for the community of<br />

species that depend <strong>on</strong> sandeels as an important food resource, the inference being that if black-legged kittiwakes are<br />

unable to breed successfully, then it is likely that sandeel abundance will be low and likely to have adverse effects <strong>on</strong><br />

many animal species. This use of black-legged kittiwakes as a sentinel assumes that a) the breeding success of blacklegged<br />

kittiwakes can easily be m<strong>on</strong>itored with a high level of accuracy, and b) that black-legged kittiwake breeding<br />

success correlates well with sandeel abundance. These prerequisites are evaluated below, together with the requirements<br />

for a useful EcoQO that human impacts are important influences, that clearly defined objectives can be set, and that the<br />

geographical range over which the EcoQ can be used is adequate.<br />

7.6.2 Can black-legged kittiwake breeding success be m<strong>on</strong>itored accurately?<br />

Black-legged kittiwakes build very c<strong>on</strong>spicuous nests in col<strong>on</strong>ies <strong>on</strong> cliff faces. The numbers of chicks in nests can<br />

easily be counted, and standardized protocols for m<strong>on</strong>itoring black-legged kittiwake breeding success are well<br />

established and widely used (Walsh et al., 1995; e.g., Mavor et al., 2002). Many amateur and professi<strong>on</strong>al ornithologists<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 33


c<strong>on</strong>tribute data to the seabird productivity m<strong>on</strong>itoring programme in Britain and Ireland. These data show clear patterns<br />

of variati<strong>on</strong>; black-legged kittiwake breeding success tends to be similar between col<strong>on</strong>ies counted independently<br />

within geographical regi<strong>on</strong>s, indicating that causes of variati<strong>on</strong> tend to affect all col<strong>on</strong>ies within a regi<strong>on</strong> (Frederiksen et<br />

al., <strong>2004</strong>). Averaging data <strong>on</strong> productivity over several col<strong>on</strong>ies within a geographical regi<strong>on</strong> reduces variance in the<br />

data c<strong>on</strong>tributed by col<strong>on</strong>y-specific factors such as local predati<strong>on</strong> impacts, weather, or disturbance effects.<br />

7.6.3 Does black-legged kittiwake breeding success correlate with sandeel abundance?<br />

To answer this questi<strong>on</strong>, we need data <strong>on</strong> black-legged kittiwake breeding success and <strong>on</strong> the local abundance of<br />

sandeels within the foraging range from breeding col<strong>on</strong>ies being m<strong>on</strong>itored. Breeding black-legged kittiwakes forage<br />

over a range typically up to 60 km from their col<strong>on</strong>y, and there are few studies of sandeel abundance in such small<br />

areas. However, the Shetland sandeel stock abundance was estimated from 1975–1994 by VPA, and from 1985–2000<br />

by research survey. The breeding success of black-legged kittiwakes at col<strong>on</strong>ies in Shetland correlates with the<br />

abundance estimates of the Shetland sandeel stock (total stock biomass) (Figures 7.6.1–7.6.3). Preliminary results from<br />

the IMPRESS study in east Scotland also show a str<strong>on</strong>g correlati<strong>on</strong> between black-legged kittiwake breeding success at<br />

col<strong>on</strong>ies in east Scotland and the annual measurement by trawl survey of 1+ sandeel abundance <strong>on</strong> the sandeel grounds<br />

east of Fife (Figure 7.6.4). Although a linear regressi<strong>on</strong> provides a good fit (R 2 = 0.839), a logistic regressi<strong>on</strong> improves<br />

the fit even further (R 2 = 0.927). The results from the IMPRESS study are not yet in the public domain and require<br />

further evaluati<strong>on</strong>, especially of the relative importance of 0 group and 1+ sandeels in affecting black-legged kittiwake<br />

ecology. Further details will be presented in late <strong>2004</strong> in the IMPRESS final report, but are not yet available to <strong>WGSE</strong>.<br />

Kittiwake breeding success at<br />

Foula<br />

1.6<br />

1.4<br />

1.2<br />

1<br />

0.8<br />

0.6<br />

y = 0.4735Ln(x) - 4.3601<br />

R 2 0.4<br />

0.2<br />

0<br />

= 0.602<br />

0 50000 100000 150000 200000<br />

Shetland sandeel total stock biomass (t<strong>on</strong>nes)<br />

Figure 7.6.1. Breeding success of black-legged kittiwakes in Foula, Shetland from 1975–1994, in relati<strong>on</strong> to the estimated abundance<br />

of sandeels at Shetland (VPA estimate of total stock biomass in t<strong>on</strong>nes; data from <strong>ICES</strong>). The fitted line is a logarithmic regressi<strong>on</strong>.<br />

Kittiwake breeding success<br />

Shetland<br />

1.2<br />

1<br />

0.8<br />

0.6<br />

y = 0.3673Ln(x) - 3.4806<br />

R2 0.4<br />

0.2<br />

0<br />

= 0.7351<br />

0 50000 100000 150000<br />

Shetland sandeel total stock biomass (t<strong>on</strong>nes)<br />

Figure 7.6.2. Breeding success of black-legged kittiwakes in selected Shetland col<strong>on</strong>ies m<strong>on</strong>itored by JNCC from 1986–1994, in<br />

relati<strong>on</strong> to the estimated abundance of sandeels at Shetland (VPA estimate of total stock biomass in t<strong>on</strong>nes; data from <strong>ICES</strong>). The<br />

fitted line is a logarithmic regressi<strong>on</strong>.<br />

34<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Kittiwake breeding success at<br />

Foula<br />

1.6<br />

1.4<br />

1.2<br />

1<br />

0.8<br />

0.6<br />

y = 0.3149Ln(x) + 0.8485<br />

R2 0.4<br />

0.2<br />

0<br />

= 0.4394<br />

0 0.5 1 1.5 2 2.5 3<br />

Sandeel abundance index (Cook)<br />

Figure 7.6.3. Breeding success of black-legged kittiwakes at Foula from 1985 to 2000, in relati<strong>on</strong> to the index of sandeel abundance<br />

at Shetland, developed by R.M. Cook (<strong>ICES</strong>, 2001, Table 13.12.3), based <strong>on</strong> research survey catch data. The fitted line is a<br />

logarithmic regressi<strong>on</strong>.<br />

Demersal trawl sandeel abundance index in the Wee Bankie/Marr Bank study.<br />

Each year from 1997 to 2003, between late May and early July, nineteen evenly spaced demersal trawl stati<strong>on</strong>s<br />

were sampled by the Scottish Fisheries Research Vessel “Clupea”. A Jacks<strong>on</strong> Rockhopper demersal trawl was<br />

towed for 30 min at a speed of approximately 4 km .h −2 at each stati<strong>on</strong>. Net geometry m<strong>on</strong>itoring equipment<br />

(SCANMAR, Norway) recorded the width and height of the trawl opening every 30 sec. The ship’s positi<strong>on</strong>,<br />

determined by Differential Global Positi<strong>on</strong>ing System (DGPS), was recorded simultaneously. Thus for each<br />

trawl sample, the area of seabed swept and the volume of water filtered by the gear could be calculated. The<br />

total catch of sandeels in each sample was quantified, as numbers per 0.5 cm size class. Length-stratified subsamples<br />

were weighed to determine length-weight relati<strong>on</strong>ships for each year. These were used to estimate<br />

weight-at-length from numbers-at-length in every trawl sample. Summing across all length classes derived<br />

estimates of total catch number and biomass. Dividing the number and weight of fish in each catch by the area<br />

of seabed swept by the trawl <strong>on</strong> each occasi<strong>on</strong> c<strong>on</strong>verted these to density estimates (no. km −2 and kg km −2 ) for<br />

each trawl stati<strong>on</strong> in each year. These density estimates were then multiplied by the area of seabed associated<br />

with each trawl stati<strong>on</strong> (Figure Box 7.1) to produce estimates of the total number and biomass of sandeels in<br />

each trawl stati<strong>on</strong> sub-area. Summing these sub-area populati<strong>on</strong> estimates across all trawl stati<strong>on</strong> sub-areas<br />

provided estimates of the total numbers and biomass of sandeels in the whole study area in each year. These<br />

abundance and biomass estimates should be c<strong>on</strong>sidered as indices <strong>on</strong>ly, since <strong>on</strong>ly a small proporti<strong>on</strong> of the<br />

water column was filtered by the gear (headline height approximately 2.8 m). It is also really <strong>on</strong>ly an index of<br />

1-group and older sandeels, since the 10 mm codend mesh-size permitted 0-group sandeels to pass through.<br />

Degrees Latitude<br />

56.5<br />

56.4<br />

56.3<br />

56.2<br />

56.1<br />

236.3<br />

191.4 329.1<br />

330.0<br />

269.1<br />

189.7<br />

190.6<br />

191.4<br />

190.1<br />

191.0<br />

284.6<br />

285.6<br />

191.4<br />

191.0<br />

333.4<br />

239.1<br />

56<br />

215.8 191.8 191.8 287.5<br />

-3 -2.8 -2.6 -2.4 -2.2 -2 -1.8 -1.6 -1.4 -1.2 -1<br />

Degrees L<strong>on</strong>gitude<br />

Figure Box 7.1. Chart showing the sea area associated with each demersal fishing stati<strong>on</strong> (numbers show area in km 2 ).<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 35


Kittiwake Breeding Success (chicks.pair -1 )<br />

1<br />

0.8<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

1997<br />

1998<br />

2002<br />

1999<br />

2001<br />

2003<br />

2000<br />

R 2 = 0.839, P


7.7 <strong>Seabird</strong> populati<strong>on</strong> trends as an index of seabird community health<br />

As pointed out by <strong>WGSE</strong> (<strong>ICES</strong>, 2003a), more detailed analyses of the empirical data <strong>on</strong> seabird populati<strong>on</strong> trends and<br />

individual col<strong>on</strong>y trends are required to fully evaluate the expected performance of the proposed EcoQ <strong>on</strong> seabird<br />

populati<strong>on</strong> trends in the North Sea as an index of seabird community health. However, the main rati<strong>on</strong>ale for this EcoQ<br />

is the general public c<strong>on</strong>cern for declining seabird populati<strong>on</strong>s. This makes it practical to define a certain level of<br />

populati<strong>on</strong> decrease that, when exceeded, should trigger investigati<strong>on</strong>s to explore the most likely causes for the decline<br />

and c<strong>on</strong>siderati<strong>on</strong>s of possible countermeasures.<br />

At any <strong>on</strong>e time, natural variability would lead half the seabird populati<strong>on</strong>s at these latitudes to increase and the other<br />

half to decrease, but our ability to detect changes over the short term depends both <strong>on</strong> the magnitude and variability of<br />

changes in time and space as well as the method(s) used. However, m<strong>on</strong>itoring of breeding seabirds aims to cover at<br />

least 10% of the total populati<strong>on</strong> of the targeted species and methods are c<strong>on</strong>sidered highly standardised and reas<strong>on</strong>ably<br />

robust. The target level previously suggested for an EcoQO (≤ 20% decline over ≥ 20 years) is also justified by the fact<br />

that seabirds are generally l<strong>on</strong>g-lived and reproduce slowly. C<strong>on</strong>sequently, rapid changes in their numbers are not<br />

expected and might indicate that some human-induced factor(s) is affecting the populati<strong>on</strong> to an extent that is not<br />

associated with a healthy seabird community and require(s) immediate management acti<strong>on</strong>s. The reference level for<br />

seabird populati<strong>on</strong> trends would typically be less than half the maximum target rate (i.e., in the order of ≤ 10% decline<br />

over ≥ 20 years).<br />

One possible opti<strong>on</strong> to make this EcoQ/EcoQO more specific is to identify the most suitable target species and key sites<br />

that could be used as a proxy for the whole North Sea seabird community, since obtaining sufficiently frequent and<br />

accurate counts of the whole North Sea populati<strong>on</strong> of breeding seabirds is not a practical propositi<strong>on</strong>. A set of principles<br />

for making such a selecti<strong>on</strong> of appropriate species and populati<strong>on</strong>s would have to take into account the distributi<strong>on</strong> of<br />

seabirds throughout different parts of the North Sea and include the most representative in terms of their ecology,<br />

numbers, distributi<strong>on</strong>, and feasibility for m<strong>on</strong>itoring (accessibility and counting accuracy). However, there are many<br />

different ways of grouping species according to their ecology (e.g., by feeding habitat and/or dietary preferences), and<br />

changes in the populati<strong>on</strong>s of species within different groups might indicate changes in the health of different<br />

comp<strong>on</strong>ents of the ecosystem.<br />

Although categorising species with respect to their ecology is certainly informative when exploring the reas<strong>on</strong>s for<br />

widespread changes in populati<strong>on</strong>s, we propose not to apply an a priori categorisati<strong>on</strong> for the purposes of m<strong>on</strong>itoring in<br />

any regi<strong>on</strong> of the North Sea. Rather, m<strong>on</strong>itoring should encompass the full suite of species that occur in significant<br />

numbers, and which can be practically m<strong>on</strong>itored to the levels required for effective analysis. When this is not possible,<br />

we do however recommend that special c<strong>on</strong>siderati<strong>on</strong> is taken to ensure that the selecti<strong>on</strong> of species includes as many<br />

ecotypes as possible. If changes are detected in more than <strong>on</strong>e species of seabird populati<strong>on</strong>, then explorati<strong>on</strong> of the<br />

possible reas<strong>on</strong>s may be directed at possible comm<strong>on</strong> causes in the ecosystem as well as reas<strong>on</strong>s that may apply to <strong>on</strong>ly<br />

individual species.<br />

<strong>WGSE</strong> discussed the completeness of the EcoQs c<strong>on</strong>sidered above. With the excepti<strong>on</strong> of the EcoQ <strong>on</strong> populati<strong>on</strong><br />

trends, all EcoQs suggest the use of seabirds as a proxy indicator of another envir<strong>on</strong>mental feature (degree of oil<br />

polluti<strong>on</strong>, mercury, organochlorine and plastic particle c<strong>on</strong>taminati<strong>on</strong>, local sandeel stocks). <strong>WGSE</strong> discussed the<br />

possible development of EcoQs <strong>on</strong> seabird diversity and <strong>on</strong> total seabird biomass and noted the possibilities of<br />

developing such EcoQs. Such metrics could also be c<strong>on</strong>sidered at the both the regi<strong>on</strong>al (country) scale and for the<br />

whole North Sea area.<br />

<strong>WGSE</strong> recognises the importance of seabird populati<strong>on</strong> parameters but cannot yet recommend an EcoQO. <strong>WGSE</strong><br />

would be prepared to c<strong>on</strong>sider these possibilities further at future meetings.<br />

7.8 References<br />

Alcock, R.E., Boumphrey, R. Malcolm, H.M., Osborn, D., and J<strong>on</strong>es, K.C. 2002. Temporal and spatial trends of PCB<br />

c<strong>on</strong>geners in UK gannet eggs. Ambio, 31: 202–206<br />

Bakker, J.F., Bartelds, W., Becker, P.H., Bester, D., Dijkshuizen, D., Fredericks, B., and Reineking, B. 1999. Marine<br />

Chemistry. Ed. by de J<strong>on</strong>g, F., Bakker, J.F., van Berkel, C.J.M., Dankers, N.M.J.A., Dahl, K., Gätje, C., Marencic,<br />

H. and Potel, P. In 1999 Wadden Sea Quality Status Report. Wadden Sea Ecosystem No. 9. Comm<strong>on</strong> Wadden Sea<br />

Secretariat, Trilateral M<strong>on</strong>itoring and Assessment <str<strong>on</strong>g>Group</str<strong>on</strong>g>, Wilhelmshaven, Germany: 85–117.<br />

Becker, P.H., Munoz Cifuentes, J., Behrends, B., and Schmieder, K.R. 2001. C<strong>on</strong>taminants in bird eggs in the Wadden<br />

Sea. Temporal and spatial trends 1991–2000. Wadden Sea Ecosystem No. 11. Comm<strong>on</strong> Wadden Sea Secretariat,<br />

Trilateral M<strong>on</strong>itoring and Assessment <str<strong>on</strong>g>Group</str<strong>on</strong>g>, Wilhelmshaven, Germany.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 37


Frederiksen, M., Harris, M., and Wanless, S. <strong>2004</strong>. Spatio-temporal pattern of black-legged kittiwake nesting success.<br />

Abstract of paper at <strong>Seabird</strong> <str<strong>on</strong>g>Group</str<strong>on</strong>g> c<strong>on</strong>ference, Aberdeen, 2–4 April <strong>2004</strong>.<br />

<strong>ICES</strong> 2001. Report of the working group <strong>on</strong> the assessment of demersal stocks in the North Sea and Skagerrak. <strong>ICES</strong><br />

<strong>CM</strong> 2001/ACFM:07.<br />

<strong>ICES</strong> 2002. Report of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong>. <strong>ICES</strong> <strong>CM</strong> 2002/C:4.<br />

<strong>ICES</strong> 2003a. Report of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong>. <strong>ICES</strong> <strong>CM</strong> 2003/C:03.<br />

<strong>ICES</strong> 2003b. Report of the Advisory Committee <strong>on</strong> Ecosystems. <strong>ICES</strong> Co-operative Research Report No. 262.<br />

Mavor, R.A., Pickerell, G., Heubeck, M., and Mitchell, P.I. 2002. <strong>Seabird</strong> numbers and breeding success in Britain and<br />

Ireland, 2000. Joint Nature C<strong>on</strong>servati<strong>on</strong> Committee, Peterborough. UK Nature C<strong>on</strong>servati<strong>on</strong>, No. 26.<br />

Moser, M.L., and Lee, D.S. 1992. A fourteen-year survey of plastic ingesti<strong>on</strong> by Western North Atlantic seabirds.<br />

Col<strong>on</strong>ial Waterbirds, 15: 83–94.<br />

OSPAR 1997. JAMP guidelines for m<strong>on</strong>itoring c<strong>on</strong>taminants in biota. 9/6/97, Oslo.<br />

OSPAR <strong>2004</strong>a. Progress in the development of the EcoQ element for local sandeel availability to black-legged<br />

kittiwakes. Paper BDC 04/02/09 to OSPAR Biodiversity Committee, Bruges, 16–20 February <strong>2004</strong>.<br />

OSPAR <strong>2004</strong>b. Proporti<strong>on</strong> of oiled guillemots am<strong>on</strong>gst those found dead or dying <strong>on</strong> beaches (North Sea Pilot Project<br />

<strong>on</strong> Ecological Quality Objectives). Paper BDC 04/02/10 to OSPAR Biodiversity Committee, Bruges 16–20<br />

February <strong>2004</strong>. Including Camphuysen C.J. 2003. North Sea pilot project <strong>on</strong> Ecological Quality Objectives, Issue<br />

4. <strong>Seabird</strong>s, EcoQO element F: Proporti<strong>on</strong> of oiled Comm<strong>on</strong> Guillemots am<strong>on</strong>g those found dead or dying <strong>on</strong><br />

beaches. Oiled-Guillemot EcoQO. Report to Biodiversity Committee (BDC) <strong>2004</strong> and OSPAR C<strong>on</strong>venti<strong>on</strong> for the<br />

Protecti<strong>on</strong> of the Marine Envir<strong>on</strong>ment of the North-east Atlantic 20<strong>05</strong>. Commissi<strong>on</strong>ed by the North Sea<br />

Directorate, Ministry of Transport, Public Works and Water Management. CSR Report <strong>2004</strong>–011.<br />

OSPAR. <strong>2004</strong>c. Summary record of Biodiversity Committee, Bruges, 16–20 February <strong>2004</strong>. Paper BDC04_SR.<br />

OSPAR. <strong>2004</strong>d. Inventory of influence of human activities <strong>on</strong> EcoQOs and identificati<strong>on</strong> of sectors and other<br />

stakeholders. Paper BDC 04/2/5 to OSPAR Biodiversity Committee, Bruges,16–20 February <strong>2004</strong>.<br />

Van Franeker, J.A., 1985. Plastic ingesti<strong>on</strong> in the North Atlantic fulmar. Marine Polluti<strong>on</strong> Bulletin 16: 367–369.<br />

Van Franeker, J.A., and Meijboom, A. 2002. LITTER NSV, Marine litter m<strong>on</strong>itoring by northern fulmars; a pilot study.<br />

Wageningen, Alterra, Green World Research. Alterra-rapport 401. 72 pp.<br />

Van Franeker J.A., and Meijboom, A. 2003. Marine litter m<strong>on</strong>itoring by northern fulmars: progress report 2002. Alterra<br />

rapport 622, Alterra Green World Research, Wageningen, 49pp.<br />

Vlietstra, L.S., and Parga, J.A. 2002. L<strong>on</strong>g-term changes in the type, but not amount, of ingested plastic particles in<br />

short-tailed shearwaters in the southeastern Bering Sea. Marine Polluti<strong>on</strong> Bulletin, 44: 945–955.<br />

Walsh, P.M., Halley, D.J., Harris, M.P., del Nevo, A., Sim, I.M.W., and Tasker, M.L. 1995. <strong>Seabird</strong> m<strong>on</strong>itoring<br />

handbook for Britain and Ireland. JNCC / RSPB / ITE / <strong>Seabird</strong> <str<strong>on</strong>g>Group</str<strong>on</strong>g>, Peterborough.<br />

8 SUMMARY OF THE SIZE, DISTRIBUTION, AND STATUS OF SEABIRD POPULATIONS IN<br />

THE NORTH SEA FOR THE PERIOD 2000–<strong>2004</strong>, AND ANY TRENDS OVER RECENT<br />

DECADES IN THESE POPULATIONS, FOR INPUT TO REGNS IN 2006.<br />

Term of Reference: start preparati<strong>on</strong>s to summarise the size, distributi<strong>on</strong> and status of seabird populati<strong>on</strong>s in the North<br />

Sea for the period 2000–<strong>2004</strong>, and any trends over recent decades in these populati<strong>on</strong>s, for input to REGNS in 2006.<br />

8.1 Introducti<strong>on</strong><br />

The status of seabirds in the North Sea (defined as <strong>ICES</strong> Areas III a-d and IV a-c) and threats to their populati<strong>on</strong>s were<br />

addressed by <strong>WGSE</strong> in 2001and 2002 (<strong>ICES</strong> 2001, 2002). Populati<strong>on</strong> trends, in some cases very approximate, were<br />

identified over the last two or three decades. <strong>WGSE</strong> has been asked to start preparati<strong>on</strong>s to summarise the size,<br />

distributi<strong>on</strong> and status of seabird populati<strong>on</strong>s in the North Sea for the period 2000–<strong>2004</strong>, identifying any trends over<br />

recent decades, for input to the Regi<strong>on</strong>al Ecosystem <str<strong>on</strong>g>Group</str<strong>on</strong>g> for the North Sea. The time period and geographical scope<br />

of focus are slightly different from those earlier terms of reference. In the present c<strong>on</strong>text the North Sea refers to <strong>ICES</strong><br />

IV a-c and III a, and it was agreed that the period of interest should be extensive and certainly initially should include<br />

all years/decades for which seabird populati<strong>on</strong> data exist.<br />

8.2 Populati<strong>on</strong> distributi<strong>on</strong> and size<br />

About 2.5 milli<strong>on</strong> pairs of seabirds breed around the coasts of the North Sea. The seas<strong>on</strong>al distributi<strong>on</strong>s, current and<br />

historical, of these populati<strong>on</strong>s are quite well-known. Some progress was made in tabulating the current status (i.e.,<br />

size) and trends of seabird populati<strong>on</strong>s in some parts of the North Sea (examples in Tables 8.1–8.4); the principal task at<br />

the outset was identified as initiating the preparati<strong>on</strong> of an audit of the available informati<strong>on</strong>. A preliminary, incomplete<br />

summary of availability of data <strong>on</strong> breeding populati<strong>on</strong> size by country follows.<br />

38<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


8.2.1 UK (<strong>ICES</strong> IVa-c)<br />

Data <strong>on</strong> populati<strong>on</strong> sizes of all seabirds in the UK with the excepti<strong>on</strong> of nocturnal Procellariiformes exist for the periods<br />

1969–70, 1985–87 and 1998–2002. Annual data are available for many col<strong>on</strong>ies for a variety of years in the latter half<br />

of the 20th century, especially since 1986. Various other data are available for selected species, e.g., northern gannet<br />

and northern fulmar, throughout the 20th century.<br />

8.2.2 Netherlands (<strong>ICES</strong> IVc)<br />

Annual populati<strong>on</strong> data for col<strong>on</strong>ies of gulls and the great cormorant exist for the Netherlands since ca. 1900. Over the<br />

same period decadal count data are available for terns.<br />

8.2.3 Norway (<strong>ICES</strong> IVa and IIIa)<br />

Data exist for cliff-breeding seabirds since ca. 1970. Derived populati<strong>on</strong> estimates exist for most species (Norwegian<br />

Institute for Nature Research, unpublished).<br />

8.2.4 Sweden (<strong>ICES</strong> IIIa)<br />

Few data are available for Swedish seabird populati<strong>on</strong>s <strong>on</strong> the North Sea coast. The latest informati<strong>on</strong> is c<strong>on</strong>tained in<br />

Svenss<strong>on</strong> et al. (1999), and indicates generally that populati<strong>on</strong>s have either remained fairly stable since the 1980s or<br />

have increased.<br />

8.2.5 Belgium (<strong>ICES</strong> IVc)<br />

No informati<strong>on</strong> was available to us for seabird populati<strong>on</strong>s in Belgium.<br />

8.2.6 Denmark (<strong>ICES</strong> IVb and IIIa)<br />

Populati<strong>on</strong> data exist for at least the great cormorant, razorbill and gulls since ca. 1920/s30, annually from ca.1980.<br />

Data (not annual) for the black guillemot and black-legged kittiwake also date from ca. 1980. In 2002, <strong>WGSE</strong> reported<br />

<strong>on</strong> populati<strong>on</strong> trends from the 1980s to 1990s in a more extensive area around the North Sea (see Grell 1998, <strong>ICES</strong><br />

2002).<br />

8.2.7 Germany (<strong>ICES</strong> IVb)<br />

Various l<strong>on</strong>g-term data sets exist for populati<strong>on</strong>s of seabirds in Germany, in some cases dating from ca.1900. <strong>WGSE</strong><br />

reported informati<strong>on</strong> <strong>on</strong> North Sea populati<strong>on</strong>s in 2002 (<strong>ICES</strong> 2002).<br />

8.3 Populati<strong>on</strong> trends<br />

<strong>WGSE</strong> recognised that seabird populati<strong>on</strong> ecology is perhaps better known than that of most other groups of marine<br />

organisms and that many kinds of populati<strong>on</strong> ecological data have been collected over many decades for a variety of<br />

species and regi<strong>on</strong>s. Given the wealth of data that are available, and are of potential use in integrative studies, <strong>WGSE</strong><br />

adopted an inclusive definiti<strong>on</strong> of populati<strong>on</strong> trends and identified a range of populati<strong>on</strong> parameters for c<strong>on</strong>siderati<strong>on</strong> in<br />

future development of this term of reference. These are indicated in Table 8.5 with a brief explanati<strong>on</strong> of their<br />

significance and an example of a recent published study.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 39


Table 8.1. Some breeding populati<strong>on</strong> sizes of seabird (number of pairs) in <strong>ICES</strong> area IVa. Data are from Lloyd et al. (1991), Mitchell<br />

et al. (<strong>2004</strong>) and the Norwegian <strong>Seabird</strong> database (Norwegian Institute for Nature Research, unpublished).<br />

40<br />

UK Norway<br />

1985–87 1998–2002 Annual change 2003<br />

Northern fulmar 341,644 318,548 −1% 1,500<br />

Manx shearwater nc 7 −<br />

European storm-petrel nc 8,929 −<br />

Leach’s storm-petrel nc 35 −<br />

Northern gannet 17,188 27,334 +4%<br />

Great cormorant 1,274 967 −2%<br />

European shag 11,909 9,042 −2% 5,000<br />

Arctic skua 2,450 1,876 −2%<br />

Great skua 5,498 9,060 +3% 5<br />

Mediterranean gull 0 0 −<br />

Black-headed gull 5,386 4,385 −1%<br />

Mew gull 1 11,026 14,589 +2% 50,000<br />

Lesser black-backed gull 2,490 1,404 −4% 98,000<br />

Herring gull 24,036 15,754 −3% 33,000<br />

Great black-backed gull 9,862 8,834 −1% 8,500<br />

Black-legged kittiwake 190,359 144,974 −2% 6,000<br />

Sandwich tern 462 172 -7%<br />

Roseate tern 0 0 -<br />

Comm<strong>on</strong> tern 1,210 1,022 −1% 7,000<br />

Arctic tern 26,527 33,246 +2% 5,100<br />

Little tern 27 29 +1%<br />

Comm<strong>on</strong> guillemot 338,331 416,435 +2% 150<br />

Razorbill 29,268 30,380 0% 300<br />

Black guillemot 21,008 22,873 +1% 380<br />

Atlantic puffin 2 115,698 117,722 0% 14,000<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Table 8.2. Some breeding populati<strong>on</strong> sizes of seabird (number of pairs) in <strong>ICES</strong> area IVb. Data are from Lloyd et al. (1991), Mitchell<br />

et al. (<strong>2004</strong>), Hälterlein and Behm-Berkelmann (1991), and Südbeck (unpublished).<br />

UK Germany<br />

1985–87 1998–2002 Annual<br />

change<br />

1990 2001–2002 Annual<br />

change<br />

Northern fulmar 13,450 14,118 < +1% 20 100 +14%<br />

Manx shearwater 0 0 −<br />

European storm-petrel 0 0 −<br />

Leach’s storm-petrel 0 0 −<br />

Northern gannet 22,371 46,662 +6% 0 130 −<br />

Great cormorant 861 1061 +2%<br />

European shag 5,402 3,218 −4%<br />

Arctic skua 0 0 −<br />

Great skua 0 0 −<br />

Mediterranean gull 0 0 − 4 2 −<br />

Little gull 1 0 −<br />

Black-headed gull 5,932 3,167 −5% 57,497 78,440 +3%<br />

Mew gull 1 189 321 +4% 4,740 6,692 +3%<br />

Lesser black-backed gull 5,580 8,848 +4% 3,155 28,382 +22%<br />

Herring gull 41,936 30,397 −2% 44,446 36,170 −2%<br />

Yellow-legged gull 11 −<br />

Great black-backed gull 31 101 +10% 3 14 +15%<br />

Gull-billed tern 46 55 +2%<br />

Black-legged kittiwake 213,236 148,593 −3% 3,700 8,000 +7%<br />

Sandwich tern 6,249 4,500 −3% 9,319 8,233 < −1%<br />

Roseate tern 49 47 < −1%<br />

Comm<strong>on</strong> tern 2,207 2,965 +2% 7,377 −<br />

Arctic tern 4,869 4,626 < −1% 6,428 −<br />

Comm<strong>on</strong>/Arctic tern 16,159 −<br />

Little tern 364 187 −5% 479 692 +4%<br />

Comm<strong>on</strong> guillemot 115,066 176,001 +3% 1,800 2,200 +2%<br />

Razorbill 13,704 20,639 +3% 6 17 +10%<br />

Black guillemot 3 3 0%<br />

Atlantic puffin 2 54,385 149,943 +8%<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 41


Table 8.3. Some breeding populati<strong>on</strong> sizes of seabird (no. of pairs) in <strong>ICES</strong> area IVc. Data are from Lloyd et al. (1991), Mitchell et<br />

al. (<strong>2004</strong>), and Dijk et al. (1999, 2003).<br />

UK Netherlands<br />

1985–87 1998–2002 Annual<br />

change<br />

Northern fulmar 455 144 −8%<br />

Manx shearwater 0 0 −<br />

European storm-petrel 0 0 −<br />

Leach's storm-petrel 0 0 −<br />

Northern gannet 0 0 −<br />

1997 2002 Annual<br />

change<br />

Great cormorant 0 40 − 17,409 22,000 +5%<br />

European shag 0 0 −<br />

Arctic skua 0 0 −<br />

Great skua 0 0 −<br />

Mediterranean gull 0 43 − 376 230 −9%<br />

Little gull − 3 2 0%<br />

Black-headed gull 21,169 33,260 +3% 140,000 135,500 < −1%<br />

Mew gull 23 22 < −1% 6,200 6,000 0%<br />

Lesser black−backed gull 5,<strong>05</strong>1 8,972 +5% 57,200 90,000 +9%<br />

Herring gull 6,443 3,485 −4% 67,000 76,500 +3%<br />

Yellow−legged gull 0 5 15 +25%<br />

Great black−backed gull 0 4 0% 8 20 +20%<br />

Gull−billed tern 0<br />

Black−legged kittiwake 2,543 1,598 −3%<br />

Sandwich tern 3,864 4,615 +1% 11,913 17,300 +8%<br />

Roseate tern 0 1<br />

Comm<strong>on</strong> tern 1,467 1,211 −1% 18,000 17,700 < −1%<br />

Arctic tern 4 8 +5% 17,063 15,500 −2%<br />

Little tern 1,456 1,087 −2% 515 450 −3%<br />

Comm<strong>on</strong> guillemot 0 0 −<br />

Razorbill 0 0 −<br />

Black guillemot 0 0 −<br />

Atlantic puffin 0 0 −<br />

42<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Table 8.4. Some breeding populati<strong>on</strong> sizes of seabird (number of pairs) in <strong>ICES</strong> area IIIa. Data are from the Norwegian <strong>Seabird</strong><br />

database (Norwegian Institute for Nature Research, unpublished).<br />

Norway<br />

2003<br />

Northern fulmar 20<br />

Northern gannet<br />

Great cormorant<br />

European shag<br />

Arctic skua<br />

Great skua<br />

Mediterranean gull<br />

Little gull<br />

Black−headed gull<br />

Mew gull 20,000<br />

Lesser black−backed gull 40,000<br />

Herring gull 20,000<br />

Yellow−legged gull<br />

Great black−backed gull 2,500<br />

Gull−billed tern<br />

Black-legged kittiwake<br />

Sandwich tern<br />

Roseate tern<br />

Comm<strong>on</strong> tern 3,000<br />

Arctic tern 100<br />

Little tern<br />

Whiskered tern<br />

Black tern<br />

Comm<strong>on</strong> guillemot<br />

Razorbill<br />

Black guillemot 30<br />

Atlantic puffin 2<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 43


Table 8.5. The availability of time series data of life history parameters of seabird populati<strong>on</strong>s in the North Sea.<br />

Parameter Availability Reference example<br />

Populati<strong>on</strong>s<br />

- breeding populati<strong>on</strong> size +++ Mavor, R.A., Pickerell, G., Heubeck, M., and Mitchell, P.I. 2002.<br />

<strong>Seabird</strong> numbers and breeding success in Britain and Ireland, 2001.<br />

Joint Nature C<strong>on</strong>servati<strong>on</strong> Committee, Peterborough (UK Nature<br />

C<strong>on</strong>servati<strong>on</strong> No. 26.)<br />

Breeding populati<strong>on</strong> size (numbers of pairs or occupied nests) is probably the most widely available parameter and there is often a<br />

legal requirement to collect such data for species of c<strong>on</strong>servati<strong>on</strong> c<strong>on</strong>cern. However, m<strong>on</strong>itoring seabird breeding numbers al<strong>on</strong>e,<br />

will not <strong>on</strong>ly fail to provide any indicati<strong>on</strong> as to the cause of a measured change in numbers, but also may present a less than optimal<br />

approach to detecting change, since specific life history parameters may vary more str<strong>on</strong>gly in resp<strong>on</strong>se to changes in food supply<br />

than would breeding numbers. Detailed time series exist for British seabird col<strong>on</strong>ies from 1986–<strong>2004</strong>. For a few species and<br />

specific col<strong>on</strong>ies, time series exist for 1900–<strong>2004</strong> <strong>on</strong> a decadal basis and in some cases an annual basis.<br />

- incidence of n<strong>on</strong>-breeding + Harris M.P., Wanless S., and Rothery P. 1986. Counts of breeding<br />

and n<strong>on</strong>-breeding Guillemots Uria aalge at a col<strong>on</strong>y during the<br />

chick rearing period. <strong>Seabird</strong>, 9: 43–46.<br />

<strong>Seabird</strong>s may forego breeding in years of low prey abundance and as such this parameter is an indicator of the state of<br />

envir<strong>on</strong>mental c<strong>on</strong>diti<strong>on</strong>s prior to the breeding seas<strong>on</strong>. A few time series may exist but are not readily available.<br />

- adult survival ++ Ratcliffe N., Catry P., Hamer K.C., Klomp N.I., and Furness R.W.<br />

2002. The effect of age and year <strong>on</strong> the survival of breeding adult<br />

Great Skuas Catharacta skua in Shetland. Ibis, 144: 384–392.<br />

In general, seabirds represent extreme K-selected species, in which adult survival is generally high, and annual reproductive output<br />

low. A significant reducti<strong>on</strong> in adult survival by causes a str<strong>on</strong>ger resp<strong>on</strong>se of populati<strong>on</strong> size than a change in most other<br />

parameters. Several time series exist, mostly for about 1985–<strong>2004</strong>.<br />

- recruitment<br />

% of cohorts that recruit + Becker P.H., H. Wendeln, and J. G<strong>on</strong>zález-Solis 2001. Populati<strong>on</strong><br />

dynamics, - recruitment, individual quality and reproductive<br />

strategies in Comm<strong>on</strong> Terns Sterna hirundo marked with<br />

transp<strong>on</strong>ders. Ardea, 89: 241–252.<br />

Juvenile mortality is in most species quite substantial and relatively few juveniles recruit into the breeding populati<strong>on</strong>. Fluctuati<strong>on</strong>s<br />

in juvenile mortality may result from poor fledging c<strong>on</strong>diti<strong>on</strong> or adverse envir<strong>on</strong>mental c<strong>on</strong>diti<strong>on</strong>s after the breeding seas<strong>on</strong>.<br />

Recruitment rates into breeding populati<strong>on</strong>s (rejuvenating the breeding stock) indicate survival of young birds and as it were<br />

“overwintering” success. In many l<strong>on</strong>g-lived seabirds, recruitment into the breeding populati<strong>on</strong> takes place after several years (up to<br />

12 years in some species). A relatively minor or at best a delayed resp<strong>on</strong>se might be expected of populati<strong>on</strong> size. A few time series<br />

exist for about 1990–<strong>2004</strong>.<br />

- recruitment age + Frederiksen, M., and T. Bregnballe. 2001. C<strong>on</strong>specific reproductive<br />

success affects age of recruitment in a great cormorant<br />

Phalacrocorax carbo sinensis col<strong>on</strong>y. - Proceedings of the Royal<br />

Society of L<strong>on</strong>d<strong>on</strong>, series B, 268: 1519–1526.<br />

In many l<strong>on</strong>g-lived seabirds, recruitment into the breeding populati<strong>on</strong> takes place after several years (up to 12 years in some<br />

species). Shifts in recruitment age may point at density dependent changes in the likelihood prospecting young birds can enter the<br />

populati<strong>on</strong>. Annual recruitment rates into the breeding populati<strong>on</strong> may indicate the quality of the col<strong>on</strong>y and year in terms of, e.g.,<br />

food supply. Some data exist, but may not provide complete time series.<br />

- immigrati<strong>on</strong> rate + Moss R., Wanless S., and Harris M.P. 2002. How small Northern<br />

Gannet col<strong>on</strong>ies grow faster than big <strong>on</strong>es. Waterbirds, 25: 442–<br />

448.<br />

The scope for immigrati<strong>on</strong> into established breeding col<strong>on</strong>ies may result from density dependent mechanisms influenced by for<br />

example per capita food supply and available nesting space. Some data exist, and there may be some time series, but often based <strong>on</strong><br />

modelling rather than purely empirical data.<br />

- per capita emigrati<strong>on</strong> rate + Frederiksen M., and Petersen A. 2000. The importance of natal<br />

dispersal in a col<strong>on</strong>ial seabird, the Black Guillemot Cepphus grylle.<br />

Ibis, 142: 48–57.<br />

The need to emigrate out of an established breeding col<strong>on</strong>y may result from density dependent mechanisms influenced by for<br />

example poor food supply and predati<strong>on</strong> rates. Modelling can be used to estimate these rates for certain well studied col<strong>on</strong>ies.<br />

44<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Table 8.5. C<strong>on</strong>tinued.<br />

HUNTING STATUS +++ Spaans A.L. 1998. Breeding Lesser Black-backed Gulls Larus<br />

graellsii in The Netherlands during the 20 th century. Sula, 12: 173–<br />

182.<br />

The most marked changes in seabird populati<strong>on</strong>s in the North Sea over the past 150 years have resulted from the relaxati<strong>on</strong> of<br />

harvesting (seabirds as food), hunting (sports, food), and persecuti<strong>on</strong> (seabirds as pests). These impacts, summarised as ‘hunting<br />

status’ may well mask envir<strong>on</strong>mental factors that impact seabird populati<strong>on</strong>s. Knowledge of statutory protecti<strong>on</strong> and periods of<br />

persecuti<strong>on</strong> are generally well known since 1900.<br />

Reproducti<strong>on</strong> and food provisi<strong>on</strong>ing<br />

- reproductive success +++ Mavor, R.A., Pickerell, G., Heubeck, M., and Mitchell, P.I. 2002.<br />

<strong>Seabird</strong> numbers and breeding success in Britain and Ireland, 2001.<br />

Joint Nature C<strong>on</strong>servati<strong>on</strong> Committee, Peterborough (UK Nature<br />

C<strong>on</strong>servati<strong>on</strong> No. 26.).<br />

Breeding success can be measured in various ways and substantial data are collected over a wide range of species (numerous<br />

col<strong>on</strong>ies, study plots) for at least several decades. Success can be measured in various ways, not detailed here, and is indicative of<br />

breeding c<strong>on</strong>diti<strong>on</strong>s and food supply. Detailed data exist as time series for many col<strong>on</strong>ies since 1986, and for a few species and<br />

col<strong>on</strong>ies for earlier decades.<br />

- laying date ++ Greenwood, J.J.D. 1983. The laying date of Razorbills Alca torda.<br />

Ibis, 124: 108.<br />

Laying is usually timed such that chicks are to be fed when food supply is at its maximum. Short summer seas<strong>on</strong>s (e.g., at high<br />

latitudes) lead to shorter windows). As early as possible breeding is often advantageous and changes in laying dates may result from<br />

climatic fluctuati<strong>on</strong>s. Time series exist for certain species and col<strong>on</strong>ies for probably several decades.<br />

- clutch size ++ Bolt<strong>on</strong> M., M<strong>on</strong>aghan P., and Houst<strong>on</strong> D.C. 1993. Proximate<br />

determinati<strong>on</strong> of clutch size in lesser black-backed gulls: the roles<br />

of food supply and body c<strong>on</strong>diti<strong>on</strong>. Canadian Journal of Zoology,<br />

71: 273–279.<br />

Favourable breeding c<strong>on</strong>diti<strong>on</strong>s will lead to a maximal clutch size, poor c<strong>on</strong>diti<strong>on</strong>s may give rise to smaller clutches. Note that many<br />

seabirds lay <strong>on</strong>ly a single egg per seas<strong>on</strong>. Time series exist for certain species and col<strong>on</strong>ies for probably several decades.<br />

- egg size ++ Furness R.W. 1984. Influences of adult age and experience, nest<br />

locati<strong>on</strong>, clutch size and laying date <strong>on</strong> the breeding success of the<br />

Great Skua Catharacta skua. Journal of Zoology, 202: 565–576.<br />

High quality parents produce better and larger eggs than c<strong>on</strong>specifics of less individual quality. Favourable breeding c<strong>on</strong>diti<strong>on</strong>s<br />

permit birds to produce better (larger) eggs. Time series exist for certain species and col<strong>on</strong>ies for probably several decades.<br />

- chick growth rate ++ Drent R.H., Klaassen, M., and Zwaan B. 1992. Predictive growth<br />

budgets in terns and gulls. In Populati<strong>on</strong> dynamics of Lari in<br />

relati<strong>on</strong> to food resources. Ed. by Spaans A.L. Ardea 80: 5–17.<br />

Favourable breeding c<strong>on</strong>diti<strong>on</strong>s (e.g., abundant food supply) make chicks grow better. Time series exist for certain species and<br />

col<strong>on</strong>ies for some years, but rarely over several decades.<br />

- mass of fledglings ++ Barrett, R.T., and Rikardsen, F. 1992. Chick growth, fledging<br />

periods and adult mass loss of Atlantic Puffins Fratercula arctica<br />

during years of prol<strong>on</strong>ged food stress. Col<strong>on</strong>ial Waterbirds, 15: 24–<br />

32.<br />

Body mass at fledging may be c<strong>on</strong>sidered an indicator of favourable growth. Time series exist for certain species and col<strong>on</strong>ies for<br />

some years, but rarely over several decades.<br />

- adult nest and brood attendance;<br />

provisi<strong>on</strong>ing rate<br />

+ Couls<strong>on</strong>, J.C., and Johns<strong>on</strong>, M.P. 1993. The attendance and absence<br />

of adult Kittiwakes Rissa tridactyla from the nest site during the<br />

chick stage. Ibis, 135: 372–378.<br />

Poor food supplies during breeding lead to prol<strong>on</strong>ged absences of parent birds at the nest and to low provisi<strong>on</strong>ing rates. Time series<br />

exist for certain species and col<strong>on</strong>ies for some years, but rarely over several decades.<br />

BODY CONDITION OF BREEDERS + Wendeln, H. 1997. Body mass of female Comm<strong>on</strong> Terns (Sterna<br />

hirundo) during courtship: relati<strong>on</strong>ships to male quality, egg mass,<br />

diet, laying date and age. Col<strong>on</strong>ial Waterbirds 20: 235–243.<br />

The body c<strong>on</strong>diti<strong>on</strong> of breeding birds is an indicator of both quality of the bird and the c<strong>on</strong>diti<strong>on</strong>s it is breeding in. Data sets are<br />

limited for most species and there are few m<strong>on</strong>itoring programmes available. Time series exist for certain species and col<strong>on</strong>ies but<br />

data are mostly just for some years.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 45


Table 8.5. C<strong>on</strong>tinued.<br />

BREEDING SEASON FOOD / DIET ++ Votier, S.C., Furness, R.W., Bearhop, S., et al. <strong>2004</strong>. Changes in<br />

fisheries discard rates and seabird communities. Nature 427: 727–<br />

730.<br />

Diet compositi<strong>on</strong> data for breeding birds are available for numerous populati<strong>on</strong>s, sometimes for series of years. Shifts in diet result<br />

from shifts in prey resources usually. Some detailed time series exist for up to 30 years, but for most species such time series<br />

are rather short.<br />

NON-BREEDING POPULATIONS ++ Kirby J.S., Gilburn A.S. and Sellers R.M. 1995. Status, distributi<strong>on</strong><br />

and habitat use by Cormorants Phalacrocorax carbo wintering in<br />

Britain. Ardea 83: 93–102.<br />

<strong>Seabird</strong>s disperse or migrate after the breeding seas<strong>on</strong> and wintering (or n<strong>on</strong>-breeding) populati<strong>on</strong>s in the North Sea include both<br />

resident seabirds as well as ‘winter visitors’ and ‘migrants’. Mid-winter censuses of waterfowl (including seaduck) are available for<br />

l<strong>on</strong>g periods with a high geographical resoluti<strong>on</strong>. Estimates of n<strong>on</strong>-breeding populati<strong>on</strong>s of pelagic seabirds are available <strong>on</strong> the<br />

basis of composite databases of offshore surveys. Although there are some time series for about 20 to 30 years, many of the<br />

data sets are of relatively low count accuracy.<br />

NON-BREEDING DIET + Wurm S. and Hüppop O. 2003. Fischereiabhängige Veränderungen<br />

in der Ernährung Helgoländer Großmöwen im Winter. Corax<br />

19(S<strong>on</strong>derheft 2): 15–26.<br />

<strong>Seabird</strong>s disperse or migrate after the breeding seas<strong>on</strong> and are therefore more difficult to approach and handle. Dietary informati<strong>on</strong><br />

may still be collected at roosts and other sites where seabirds c<strong>on</strong>gregate <strong>on</strong> land, but for most pelagic species it is very difficult to<br />

collect dietary informati<strong>on</strong>. Few l<strong>on</strong>g time series are likely to be available.<br />

NON-BREEDING DISTRIBUTION ++ St<strong>on</strong>e, C.J., A. Webb, C. Bart<strong>on</strong>, N. Ratcliffe, T.C. Reed, M.L.<br />

Tasker, C.J. Camphuysen and M.W. Pienkowski. 1995. An atlas of<br />

seabird distributi<strong>on</strong> in north-west European waters. Joint Nature<br />

C<strong>on</strong>servati<strong>on</strong> Committee, Peterborough.<br />

<strong>Seabird</strong>s disperse or migrate after the breeding seas<strong>on</strong> and wintering (or n<strong>on</strong>-breeding) populati<strong>on</strong>s in the North Sea include both<br />

resident seabirds as well as ‘winter visitors’ and ‘migrants’. Mid-winter censuses of waterfowl (including seaduck) are available for<br />

l<strong>on</strong>g periods with a high geographical resoluti<strong>on</strong> (coastal wetlands). N<strong>on</strong>-breeding distributi<strong>on</strong>s of pelagic seabirds are available in<br />

the form of composite maps of n<strong>on</strong>-breeding distributi<strong>on</strong> based <strong>on</strong> series of years work, often in areas that differ between seas<strong>on</strong>s.<br />

Comparis<strong>on</strong>s may be made between decades, but annual data are unlikely to be of sufficient resoluti<strong>on</strong> to provide annual<br />

time series.<br />

TIMING OF MIGRATION ++ Camphuysen C.J. and Dijk J.van 1983. Zee- en kustvogels langs de<br />

Nederlandse kust, 1974–79. Limosa, 56: 81–230.<br />

Coastal seawatching results provide informati<strong>on</strong> <strong>on</strong> the timing and strength of seabird passage during spring and autumn migrati<strong>on</strong>.<br />

The median date of passage does change from year to year, possibly in resp<strong>on</strong>se to climatic fluctuati<strong>on</strong>s. There are probably some<br />

quite l<strong>on</strong>g time series though possibly not readily extracted from readily available data sets.<br />

+++ large scale, l<strong>on</strong>g time series; ++ moderate data; + few data<br />

8.4 Future development of this term of reference<br />

Further progress with this term of reference will begin with completi<strong>on</strong> of an audit of available data and possible<br />

creati<strong>on</strong> of a metadatabase of available time series <strong>on</strong> aspects of seabird populati<strong>on</strong> ecology, and compilati<strong>on</strong> of<br />

breeding populati<strong>on</strong> database.<br />

8.5 Additi<strong>on</strong>al references<br />

Dijk, A.J. van, Kleefstra, R., Zoetebier, D., and Meijer, R. 1999. Kol<strong>on</strong>ievogels en zeldzame broedvogels in Nederland<br />

in 1997. SOVON M<strong>on</strong>itoringrapport 1999/09, SOVON, Beek-Ubbergen.<br />

Dijk, A.J. van, Hustings, F., Koffijberg, K., Weide, M. van der, Zoetebier, D. and Plate, C., 2003. Kol<strong>on</strong>ievogels en<br />

zeldzame broedvogels in Nederland in 2002. SOVON-m<strong>on</strong>itoringrapport 2003/02. SOVON, Beek-Ubbergen.<br />

Grell, M.B. 1998. Fuglenes Danmark. Gads Forlag, Viborg. 825 pp. (In Danish).<br />

Hälterlein, B. and Behm-Berkelmann, K. 1991. Brutvogelbestände an der deutschen Nordseeküste im Jahre 1990 –<br />

Vierte Erfassung durch die Arbeitgemeinschaft “Seevogelschutz”. Seevögel 12: 47–51.<br />

<strong>ICES</strong>. 2001. Report of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong>. <strong>ICES</strong> <strong>CM</strong> 2001/C:<strong>05</strong>.<br />

<strong>ICES</strong>. 2002. Report of the <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong>. <strong>ICES</strong> <strong>CM</strong> 2002/C:04.<br />

Lloyd, C., Tasker, M. L., and Pertridge, K. 1991. The status of seabirds in Britain and Ireland. T and A D Poyser,<br />

L<strong>on</strong>d<strong>on</strong>. 355 pp.<br />

Mitchell, P.I., Newt<strong>on</strong> S.F., Ratcliffe, N., and Dunn T.E. <strong>2004</strong>. <strong>Seabird</strong> Populati<strong>on</strong>s of Britain and Ireland. T and AD<br />

Poyser, L<strong>on</strong>d<strong>on</strong>.<br />

46<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Norwegian Institute for Nature Research. Norwegian <strong>Seabird</strong> Database. Unpublished, Tr<strong>on</strong>dheim.<br />

Südbeck, P. unpublished data from NiedersächsischesLandesant für Ökologie, Landesant für den Nati<strong>on</strong>alpark<br />

Schleswig-HolsteinischesWattenmeer; Verein Jordsand, 2002.<br />

Svenss<strong>on</strong>, S., Svenss<strong>on</strong>, M., and Tjernberg, M. 1999. Svensk fågelatlas. Vår Fågelvärld, supplement 31, Stockholm,<br />

550 pp.<br />

9 RECOMMENDATIONS<br />

9.1 Chair of <strong>WGSE</strong><br />

The <strong>WGSE</strong> unanimously recommends that Dr Stefan Garthe, FTZ, University of Kiel, Hafentörn, D-25761Büsum,<br />

Germany, should be invited to Chair <strong>WGSE</strong> from 1 January 20<strong>05</strong>.<br />

9.2 Proposal for next meeting<br />

The <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong> makes the following proposals:<br />

The <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong> [<strong>WGSE</strong>] (Chair: Dr Stefan Garthe*, Germany) will meet in Texel, The<br />

Netherlands from 29 March–1 April 20<strong>05</strong> to:<br />

a) C<strong>on</strong>tinue to summarize the size, distributi<strong>on</strong> and status of seabird populati<strong>on</strong>s in the North Sea for the period<br />

2000–<strong>2004</strong>, and any trends over recent decades in these populati<strong>on</strong>s, for input to REGNS in 2006;<br />

b) Develop EcoQOs for seabird populati<strong>on</strong>s;<br />

c) Review the impacts of recent major oil spills <strong>on</strong> seabirds (“Erika”, “Prestige”, “Tricolor”);<br />

d) Review the c<strong>on</strong>sequences for foraging c<strong>on</strong>diti<strong>on</strong>s of sea ducks of the Spisula decline in the southern North Sea;<br />

e) Examine the foodweb relati<strong>on</strong>ships of seabirds indicated by food c<strong>on</strong>sumpti<strong>on</strong> estimates in the Northeast and<br />

Northwest Atlantic regi<strong>on</strong>s.<br />

Supporting informati<strong>on</strong><br />

Priority: This is the <strong>on</strong>ly major forum for work being carried out by <strong>ICES</strong> in relati<strong>on</strong> to marine birds. If<br />

<strong>ICES</strong> wishes to maintain its profile in this area of work, then the activities of <strong>WGSE</strong> must be<br />

regarded as of high priority.<br />

Scientific<br />

justificati<strong>on</strong> and<br />

relati<strong>on</strong> to Acti<strong>on</strong><br />

Plan<br />

Acti<strong>on</strong> Plan Nos. 1.2, 1.8, 2.2, 2.3, 4.15.<br />

a) This Term of Reference c<strong>on</strong>tinues the work requested by <strong>ICES</strong> to provide data sets for the<br />

integrated assessment of the North Sea under the coordinati<strong>on</strong> of REGNS;<br />

b) Although <strong>WGSE</strong> has recommended several EcoQOs using seabirds as a means of measuring<br />

c<strong>on</strong>taminants or ecological c<strong>on</strong>diti<strong>on</strong>s in the North Sea (oil polluti<strong>on</strong>, mercury,<br />

organochlorines, plastic, sandeel availability to predators), EcoQOs for seabirds have not been<br />

fully developed. Here we propose a discussi<strong>on</strong> of the possible metrics and objectives for seabird<br />

populati<strong>on</strong>s themselves, such as rates of change in breeding populati<strong>on</strong> size, seabird community<br />

compositi<strong>on</strong>, biomass or diversity measures;<br />

c) Although it is a well-established opini<strong>on</strong> that chr<strong>on</strong>ic oil polluti<strong>on</strong> tends to impose a greater<br />

mortality <strong>on</strong> seabirds than that caused by the infrequent major oil spill events, the recent spills<br />

from the “Erika”, “Prestige” and “Tricolor” appear to have killed very large numbers of<br />

seabirds. We c<strong>on</strong>sider that it would be instructive to review the studies carried out <strong>on</strong> these<br />

three major incidents and the m<strong>on</strong>itoring of seabird populati<strong>on</strong>s likely to have been affected by<br />

these spills;<br />

d) Stocks of Spisula in the southern North Sea have decreased c<strong>on</strong>siderably in recent years, and<br />

the abundance of Ensis has increased. Sea ducks, especially scoters, have switched to feeding<br />

<strong>on</strong> Ensis despite the apparent low suitability of that food. We propose reviewing the changes in<br />

foodweb relati<strong>on</strong>ships of these ducks and their winter ecology that have resulted from the<br />

changes in shellfish stocks;<br />

e) <strong>WGSE</strong> has worked for several years <strong>on</strong> assessing the seabird community compositi<strong>on</strong>,<br />

trophic relati<strong>on</strong>s and energy c<strong>on</strong>sumpti<strong>on</strong> of seabirds in the <strong>ICES</strong> and NAFO Regi<strong>on</strong>s. Having<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 47


Resource<br />

requirements:<br />

identified major differences in trophic ecology of seabirds between <strong>ICES</strong> and NAFO Regi<strong>on</strong>s,<br />

we propose c<strong>on</strong>tinuing this work by examining these patterns further, and in particular relating<br />

the differences to possible differences in lower trophic levels, seabird habitats or oceanography<br />

between the east and west North Atlantic.<br />

In order to carry out work <strong>on</strong> the proposed Terms of Reference there may be a need to add<br />

some new members to the <strong>WGSE</strong>, particularly individuals with expertise in sea duck ecology in<br />

the southern North Sea. Facilities for <strong>WGSE</strong> to work in Texel are anticipated to be excellent.<br />

Participants: The <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> should be able to achieve most of the above objectives. However, some<br />

members may not be able to attend through lack of funding. Funding of these members from<br />

Member Countries would be very welcome.<br />

Secretariat Facilities: The usual excellent support from the Secretariat will be appreciated.<br />

Financial: No financial implicati<strong>on</strong>s for <strong>ICES</strong>.<br />

Linkages to advisory<br />

committees:<br />

Linkages to other<br />

committees or<br />

groups:<br />

Linkages to other<br />

organisati<strong>on</strong>s:<br />

48<br />

Both ACFM and ACE would find the informati<strong>on</strong> <strong>on</strong> c<strong>on</strong>sumpti<strong>on</strong> by seabirds of relevance to<br />

the forthcoming multispecies modelling of the North Sea, and to assessing envir<strong>on</strong>mental needs<br />

of seabirds and effects of seabirds <strong>on</strong> fish stocks.<br />

<strong>WGSE</strong> is keen to c<strong>on</strong>tinue the process of integrati<strong>on</strong> of seabird ecology into the workings of<br />

<strong>ICES</strong>, and warmly welcomes the initiative of REGNS.<br />

Informati<strong>on</strong> <strong>on</strong> seabird communities, populati<strong>on</strong> trends and envir<strong>on</strong>mental impacts should also<br />

be of interest to OSPAR and HELCOM.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


10 ANNEXES<br />

Annex 1 List of participants<br />

Name Address Teleph<strong>on</strong>e Telefax E-mail<br />

Tycho Anker- NINA, Tungasletta 2<br />

+47 7380 1443 +47 7380 1401 tycho@nina.no<br />

Nilssen NO-7485 Tr<strong>on</strong>dheim<br />

Norway<br />

Rob Barrett Tromsø University Museum<br />

Zoology Department<br />

N-9037 Tromsø<br />

Norway<br />

+47 77645013 +47 77645520 robb@tmu.uit.no<br />

Peter Becker Institut für Vogelforschung<br />

Vogelwarte Helgoland,<br />

An der Vogelwarte 21<br />

D-26386 Wilhelmshaven<br />

Germany<br />

+49 4421 96890 +49 4421 968955 peter.becker@ifv.terramare.de<br />

Kees<br />

Royal Netherlands Institute for +31 222 369488 +31 222 319674 camphuys@nioz.nl<br />

Camphuysen Sea Research<br />

PO Box 59<br />

1790 AB Den Burg<br />

Texel<br />

The Netherlands<br />

Gilles<br />

Service Canadien de la Faune +1 4186496127 +1 4186485511 gilles.chapdelaine@ec.gc.ca<br />

Chapdelaine Envir<strong>on</strong>ment Canada CWS<br />

1141, route de l’Eglise, Ste-Foy<br />

Quebec G1V 4H5<br />

Canada<br />

Morten CEH Banchory<br />

+44 1330 826338 +44 1330 823303 mfr@ceh.ac.uk<br />

Frederiksen Hill of Brathens<br />

Glassel<br />

Banchory AB31 4BW<br />

United Kingdom<br />

Bob Furness University of Glasgow,<br />

+44 1413303560 +44 14133<strong>05</strong>971 r.furness@bio.gla.ac.uk<br />

(Chair) Graham Kerr Building,<br />

Glasgow G12 8QQ,<br />

United Kingdom<br />

Stefan Garthe FTZ, University of Kiel<br />

Hafentörn<br />

D-25761 Büsum<br />

Germany<br />

+49 4834 604 116 +49 4834 604 199 garthe@ftz-west.uni-kiel.de<br />

Anders Dept. of Arctic Envir<strong>on</strong>ment +45 4630 1934 +45 4630 1914 amo@dmu.dk<br />

Mosbech Nati<strong>on</strong>al Envir<strong>on</strong>mental<br />

Research Institute<br />

Frederiksborgvej 399<br />

PO Box 358<br />

DK-4000 Roskilde<br />

Denmark<br />

Daniel Oro Institut Mediterrani d'Estudis<br />

Avançats IMEDEA<br />

CSIC-UIB<br />

Miquel Marques 21<br />

07190 Esporles<br />

Spain<br />

+34 971611731 +34 971611761 d.oro@uib.es<br />

Jim Reid Joint Nature C<strong>on</strong>servati<strong>on</strong><br />

Committee<br />

Dunnet House,<br />

7 Thistle Place<br />

Aberdeen AB10 1UZ<br />

United Kingdom<br />

+44 1224 655702 +44 1224 621488 jim.reid@jncc.gov.uk<br />

Mark Tasker Joint Nature C<strong>on</strong>servati<strong>on</strong><br />

Committee<br />

Dunnet House, 7<br />

Thistle Place<br />

Aberdeen AB10 1UZ<br />

United Kingdom<br />

+44 1224 655701 +44 1224 621488 mark.tasker@jncc.gov.uk<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 49


Annex 2 Terms of Reference<br />

The <str<strong>on</strong>g>Working</str<strong>on</strong>g> <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> <strong>Seabird</strong> <strong>Ecology</strong> [<strong>WGSE</strong>] (Chair: R.W. Furness, UK) will meet in Aberdeen, U.K. from 29<br />

March–2 April <strong>2004</strong> to:<br />

a) review the factors influencing trends in abundance of seabirds in the Baltic Sea;<br />

b) review progress in studies of seabirds in relati<strong>on</strong> to marine wind farms;<br />

c) review relati<strong>on</strong>ships between seabirds and oceanographic features, with particular reference to effects of climate<br />

change;<br />

d) c<strong>on</strong>sider the selecti<strong>on</strong> of seabird species and populati<strong>on</strong>s that would be appropriate to use in an EcoQO relating to<br />

seabird populati<strong>on</strong> trends in the North Sea as indices of seabird community health;<br />

e) complete the work carried out in 2003 to compare seabird communities and prey c<strong>on</strong>sumpti<strong>on</strong> between the east<br />

and west North Atlantic;<br />

f) provide the Study <str<strong>on</strong>g>Group</str<strong>on</strong>g> <strong>on</strong> Multispecies Assessments in the North Sea (SGMSNS) with data <strong>on</strong> the c<strong>on</strong>sumpti<strong>on</strong><br />

of different prey by seabirds in the North Sea, in a format specified by SGMSNS;<br />

g) rec<strong>on</strong>sider the formulati<strong>on</strong> of the EcoQOs listed below, determine whether a more specific EcoQO is needed in<br />

terms of its specificati<strong>on</strong> to the metric, time and geographical area, and as necessary propose more specific<br />

EcoQO(s) [OSPAR <strong>2004</strong>/1]:<br />

i) EcoQ element (f) Proporti<strong>on</strong> of oiled comm<strong>on</strong> guillemots am<strong>on</strong>g those found dead or dying <strong>on</strong> beaches,<br />

ii) EcoQ element (g) Mercury c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs and feathers,<br />

iii) EcoQ element (h) Organochlorine c<strong>on</strong>centrati<strong>on</strong>s in seabird eggs,<br />

iv) EcoQ element (i) Plastic particles in stomachs of seabirds;<br />

v) EcoQ element (j) Local sandeel availability to black-legged kittiwakes,<br />

vi) EcoQ element (k) <strong>Seabird</strong> populati<strong>on</strong> trends as an index of seabird community health.<br />

h) start preparati<strong>on</strong>s to summarise the size, distributi<strong>on</strong> and status of seabird populati<strong>on</strong>s in the North Sea for the<br />

period 2000–<strong>2004</strong>, and any trends over recent decades in these populati<strong>on</strong>s, for input to REGNS in 2006.<br />

<strong>WGSE</strong> will report by 30 April <strong>2004</strong> for the attenti<strong>on</strong> of the Oceanography Committee, A<strong>CM</strong>E, and ACE.<br />

Supporting informati<strong>on</strong><br />

Priority: This is the <strong>on</strong>ly major forum for work being carried out by <strong>ICES</strong> in relati<strong>on</strong> to marine birds. If <strong>ICES</strong> wishes<br />

to maintain its profile in this area of work, then the activities of <strong>WGSE</strong> must be regarded as of high priority.<br />

Scientific<br />

justificati<strong>on</strong>:<br />

50<br />

a) <strong>WGSE</strong> reviewed data <strong>on</strong> populati<strong>on</strong> trends of seabirds in the Baltic Sea in the 2003 meeting. Given that<br />

there have been major declines in numbers of certain populati<strong>on</strong>s and species, it is important to review<br />

likely causes of these declines, and factors that may have c<strong>on</strong>tributed to the increase in numbers in a<br />

few species;<br />

b) With a rapid development of marine wind farms in many European countries, the <str<strong>on</strong>g>Group</str<strong>on</strong>g> should review<br />

progress in the areas that have been identified as major gaps in knowledge; two of the most important<br />

of these are the development of methods to measure bird collisi<strong>on</strong> risk, and the behavioural resp<strong>on</strong>ses<br />

of birds to marine wind farms (such as avoidance causing possible loss of foraging habitat, barriers to<br />

movement, and use of marine wind farms as new habitat for resting or feeding);<br />

c) There has been a large increase in work <strong>on</strong> the extent to which at-sea distributi<strong>on</strong>s of seabirds are<br />

determined by oceanographic factors. This has been partly by at-sea survey work, and partly by the<br />

applicati<strong>on</strong> of data loggers <strong>on</strong> foraging seabirds. Recent research also indicates effects of climate<br />

change <strong>on</strong> seabird distributi<strong>on</strong>, demography and ecology. It would be useful to review this progress.<br />

d) The proposed EcoQO ‘<strong>Seabird</strong> populati<strong>on</strong> trends in the North Sea as an index of seabird community<br />

health requires further work with empirical data <strong>on</strong> seabird populati<strong>on</strong> trends and individual col<strong>on</strong>y<br />

trends in order that the historical trajectories and performance of the various possible metrics can be<br />

evaluated, especially in relati<strong>on</strong> to the use of particular focal species and selected key sites as a proxy<br />

for the whole North Sea species’ populati<strong>on</strong>s (since obtaining accurate and frequent whole-North Sea<br />

counts of seabird breeding populati<strong>on</strong>s is not a practical propositi<strong>on</strong>). During the 2003 <strong>WGSE</strong> meeting<br />

we had neither the necessary data, nor the time to perform these analyses.<br />

e) <strong>WGSE</strong> 2002 meeting completed a summary of the breeding seabird numbers by species, and total<br />

seabird energy requirements, and approximate food c<strong>on</strong>sumpti<strong>on</strong> equivalents, in all <strong>ICES</strong> areas<br />

(approximately described as the ‘east North Atlantic’). Given the pr<strong>on</strong>ounced differences in seabird<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


Relati<strong>on</strong> to strategic<br />

plan:<br />

Resource<br />

requirements:<br />

community compositi<strong>on</strong> and species abundances, and in fish stocks and fisheries, between the west and<br />

east North Atlantic, <strong>WGSE</strong>03 c<strong>on</strong>firmed that it is instructive to compare and c<strong>on</strong>trast the patterns of<br />

seabird community compositi<strong>on</strong> and energy requirements between <strong>ICES</strong> and NAFO areas<br />

(approximately ‘west’ and ‘east’ North Atlantic), in relati<strong>on</strong> to broad differences in the histories of fish<br />

stocks and fisheries in these areas.<br />

f) WGMSNS require a compilati<strong>on</strong> of data <strong>on</strong> quantities of foods c<strong>on</strong>sumed by seabirds in the North Sea<br />

for input to an MSVPA model. These data will be compiled in the format required by WGMSNS.<br />

g) This is to resp<strong>on</strong>d to an OSPAR request.<br />

h) This is required as the working groups input to the thematic writing panels working under the coordinati<strong>on</strong><br />

of REGNS to develop an integrated assessment of the North Sea. For the purposes of this<br />

study the North Sea comprises <strong>ICES</strong> Area IV and IIIa and does not include intertidal areas. As far as<br />

possible, significant seas<strong>on</strong>al variati<strong>on</strong> should be described.. Where possible, the causes of any trends<br />

should be outlined.<br />

The above will help achieve the following within the initial <strong>ICES</strong> strategic plan<br />

Goal 1. Develop a challenging core science programme to fulfil the <strong>ICES</strong> Missi<strong>on</strong>.<br />

Goal 2. Provide sound, credible, timely, and understandable advice that is relevant to today’s and future<br />

societal needs.<br />

Goal 5. Raise public understanding of marine ecosystems and their relevance to society.<br />

Objective 1. Understand the physical, chemical, and biological functi<strong>on</strong>ing of marine ecosystems.<br />

Objective 2. Understand and quantify human impacts <strong>on</strong> the marine envir<strong>on</strong>ment, including living marine<br />

resources.<br />

Objective 3. Develop the scientific basis for sustainable use and protecti<strong>on</strong> of the marine envir<strong>on</strong>ment,<br />

including living marine resources.<br />

Objective 4. Provide advice <strong>on</strong> the sustainable use and protecti<strong>on</strong> of the marine envir<strong>on</strong>ment, including<br />

living marine resources.<br />

Objective 5. Co-ordinate and support interdisciplinary and internati<strong>on</strong>al marine science programmes.<br />

Objective 6. Broaden the diversity of the scientists that participate in <strong>ICES</strong> activities.<br />

Objective 11. Make the scientific products of <strong>ICES</strong> more accessible to the public<br />

There will be a major c<strong>on</strong>ference <strong>on</strong> <strong>Seabird</strong>s in Aberdeen starting <strong>on</strong> Friday 2 April <strong>2004</strong>. Since all active<br />

members of the group are at present funded outside core funding within the Member Countries (many are<br />

privately funded), meeting in Aberdeen immediately before this c<strong>on</strong>ference will minimise travel costs of<br />

members, as most are likely to be attending the c<strong>on</strong>ference.<br />

Participants: The present members of the group should be able to achieve most of the above objectives. However, some<br />

may not be able to attend through lack of funding. Funding of these members from Member Countries<br />

would be very welcome.<br />

Secretariat<br />

Facilities:<br />

N/A<br />

Financial: No financial implicati<strong>on</strong>s for <strong>ICES</strong>.<br />

Linkages to<br />

advisory<br />

committees:<br />

Linkages to other<br />

committees or<br />

groups:<br />

Linkages to other<br />

organisati<strong>on</strong>s:<br />

Cost Share <strong>ICES</strong> 100%<br />

Both ACFM and ACE would find the informati<strong>on</strong> <strong>on</strong> c<strong>on</strong>sumpti<strong>on</strong> by seabirds of relevance to the<br />

forthcoming multispecies modelling of the North Sea, and to assessing envir<strong>on</strong>mental needs of seabirds and<br />

effects of seabirds <strong>on</strong> fish stocks.<br />

<strong>WGSE</strong> is keen to c<strong>on</strong>tinue the process of integrati<strong>on</strong> of seabird ecology into the workings of <strong>ICES</strong>.<br />

Several nati<strong>on</strong>al governments have encouraged the development of at-sea wind farms to increase the<br />

proporti<strong>on</strong> of electricity generated from renewable resources. Review of the impacts of at-sea wind farms <strong>on</strong><br />

seabirds will be of interest to several statutory agencies and NGOs.<br />

Informati<strong>on</strong> <strong>on</strong> seabird communities, populati<strong>on</strong> trends and envir<strong>on</strong>mental impacts should also be of interest<br />

to OSPAR and HELCOM.<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 51


Annex 3 English and scientific names of birds menti<strong>on</strong>ed in this report<br />

52<br />

English name Scientific name<br />

Red-throated diver Gavia stellata<br />

Black-throated diver Gavia arctica<br />

Great northern diver Gavia immer<br />

Slav<strong>on</strong>ian grebe Podiceps auritus<br />

Great crested grebe Podiceps griseigena<br />

Red-necked grebe Podiceps grisegena<br />

Little grebe Tachybaptus ruficollis<br />

Wandering albatross Diomedea exulans<br />

Black-browed albatross Thalassarche melanophrys<br />

Sooty albatross Phoebetria fusca<br />

Light mantled sooty alb. Phoebetria palpebrata<br />

Blue petrel Halobaena caerulea<br />

Thin-billed pri<strong>on</strong> Pachyptila belcheri<br />

Northern fulmar Fulmarus glacialis<br />

Southern fulmar Fulmarus glacialoides<br />

Grey petrel Procellaria cinerea<br />

Cory’s shearwater Cal<strong>on</strong>ectris diomedea<br />

Great shearwater Puffinus gravis<br />

Little shearwater Puffinus assimilis<br />

Audub<strong>on</strong>’s shearwater Puffinus lherminieri<br />

Balearic shearwater Puffinus mauretanicus<br />

Manx shearwater Puffinus puffinus<br />

Sooty shearwater Puffinus griseus<br />

Bulwer’s petrel Bulweria bulwerii<br />

European storm-petrel Hydrobates pelagicus<br />

White-faced storm-petrel Pelagodroma marina<br />

Leach’s storm-petrel Oceanodroma leucorhoa<br />

Madeiran storm-petrel Oceanodroma castro<br />

Wils<strong>on</strong>’s storm-petrel Oceanites oceanicus<br />

Black-capped petrel Pterodroma hasitata<br />

Zino’s petrel Pterodroma madeira<br />

White-headed petrel Pterodroma less<strong>on</strong>i<br />

Fea’s petrel Pterodroma feae<br />

Northern gannet Morus bassanus<br />

Great cormorant Phalacrocorax carbo<br />

Double-crested cormorant Phalacrocorax auritus<br />

European shag Phalacrocorax aristotelis<br />

Mute swan Cygnus olor<br />

Whooper swan Cygnus cygnus<br />

Comm<strong>on</strong> shelduck Tadorna tadorna<br />

Pintail Anas acuta<br />

Eurasian teal Anas crecca<br />

Eurasian wige<strong>on</strong> Anas penelope<br />

Mallard Anas platyrhynchos<br />

Greater scaup Aythya marila<br />

Pochard Aythya ferina<br />

Tufted duck Aythya fuligula<br />

Comm<strong>on</strong> eider Somateria mollissima<br />

King eider Somateria spectabilis<br />

Steller’s eider Polysticta stelleri<br />

Harlequin duck Histri<strong>on</strong>icus histri<strong>on</strong>icus<br />

L<strong>on</strong>g-tailed duck Clangula hyenalis<br />

Black scoter Melanitta nigra<br />

Velvet scoter Melanitta fusca<br />

Surf scoter Melanitta perspicillata<br />

Comm<strong>on</strong> goldeneye Bucephala clangula<br />

Red-breasted merganser Mergus serrator<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong>


English name Scientific name<br />

Goosander Mergus merganser<br />

Smew Mergellus albellus<br />

Eurasian coot Fulica atra<br />

Eurasian oystercatcher Haematopus ostralegus<br />

Red-necked phalarope Phalaropus lobatus<br />

Grey phalarope Phalaropus fulicarius<br />

Arctic skua Stercorarius parasiticus<br />

Pomarine skua Stercorarius pomarinus<br />

Great skua Stercorarius skua<br />

Mediterranean gull Larus melanocephalus<br />

Little gull Larus minutus<br />

Black-headed gull Larus ridibundus<br />

Sabine’s gull Larus sabini<br />

Mew ( = Comm<strong>on</strong>) gull Larus canus<br />

B<strong>on</strong>aparte’s gull Larus philadelphia<br />

Laughing gull Larus atricilla<br />

Ring-billed gull Larus delawarensis<br />

Audouin’s gull Larus audouinii<br />

Slender-billed gull Larus genei<br />

Lesser black-backed gull Larus fuscus<br />

Glaucous gull Larus hyperboreus<br />

Iceland gull Larus glaucoides<br />

Herring gull Larus argentatus<br />

Yellow-legged gull Larus cachinnans<br />

Great black-backed gull Larus marinus<br />

Ivory gull Pagophila eburnean<br />

Black-legged kittiwake Rissa tridactyla<br />

Gull-billed tern Gelochelid<strong>on</strong> nilotica<br />

Roseate tern Sterna dougallii<br />

Forster’s tern Sterna forsteri<br />

Comm<strong>on</strong> tern Sterna hirundo<br />

Arctic tern Sterna paradisaea<br />

Little tern Sterna albifr<strong>on</strong>s<br />

Least tern Sterna antillarum<br />

Sandwich tern Sterna sandvicensis<br />

Royal tern Sterna maxima<br />

Caspian tern Sterna caspia<br />

Black tern Chlid<strong>on</strong>ias niger<br />

Black skimmer Rynchops niger<br />

Comm<strong>on</strong> guillemot Uria aalge<br />

Brunnich’s guillemot Uria lomvia<br />

Razorbill Alca torda<br />

Black guillemot Cepphus grylle<br />

Little auk Alle alle<br />

Least auklet Aethia pusilla<br />

Atlantic puffin Fratercula arctica<br />

Tufted puffin Fratercula cirrhata<br />

Horned puffin Fratercula corniculata<br />

<strong>ICES</strong> <strong>WGSE</strong> Report <strong>2004</strong> 53

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