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

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Table 5.7. Approximate numbers (individuals x 1000) and biomass (tonnes) of birds that breed outside NAFO subareas but enter NAFO 5 and 6 (from ICES. 2003, Table 3.4). Species Number Biomass Greater shearwater 1900 2100 Sooty shearwater 410 320 Wilson’s storm-petrel 600 20 Long-tailed duck 230 190 Black scoter 60 60 Surf scoter 120 150 Velvet scoter 100 130 Red-breasted merganser 60 40 Red-necked phalarope 250 10 Grey phalarope 240 10 Bonaparte’s gull 60 10 Ring-billed gull 1500 600 Total 5530 3640 5.2.3 Consumption estimates Seabirds occupying the NAFO and ICES areas of the North Atlantic consume an estimated 11.5 million tonnes of food per year with 45% being taken in the western sector and 55% in the east. This total is ca. 10–20% of the total consumption by the world’s seabirds (max. CI range = 56–133 million tonnes) estimated by Brooke (2003). Although this percentage seems relatively high, it may reflect both the elevated consumption by seabirds at high latitudes and the conservative approach of Brooke’s estimate. The near equality of the overall consumption on both sides of the Atlantic is despite the fact that nearly twice the number of seabirds occupies the NAFO areas and is a reflection of the huge numbers of small species in the west. The total food consumption estimates for both the ICES subareas and for the NAFO subareas peak in the summer season at levels 44% and 54% higher than the respective winter consumption estimates. The elevated energy demand in summer is primarily caused by increased reproduction activity, but also the larger numbers of birds (and hence higher biomass) in summer on both sides of the Atlantic. In the ICES area there are 37% more birds (and an 11% higher biomass) and in the NAFO area 12% more birds (and 16% higher biomass) in summer than in winter. In the NAFO area the extra food consumption caused by reproduction and the summer visitors from the southern hemisphere outweigh by far the extra consumption by wintering visitors entering the NAFO area from the ICES area and the eastern Canadian Arctic (guillemots and seaducks) and leaving the NAFO area for the summer. Note that while numbers and biomass of seabirds in a given area in a given season are based on maximum numbers in that season, the food consumption of seabirds occupying the ICES subareas (Table 5.8) and the NAFO subareas (Table 5.9) are calculated based on the number of days each species stays in a given subarea and thus do not directly correspond to the biomass in Tables 5.5 and 5.6. 24 ICES WGSE Report 2004
Table 5.8. Approximate food consumption (tonnes x 1000) by seabirds occupying ICES subareas in winter, spring, summer, and autumn. ICES subarea Winter Spring Summer Autumn Total I,IIa,IIb Barents and Norwegian Seas 270 360 570 450 1650 Va,XIVa,b E. Greenland and Iceland 380 470 690 530 2080 IVa-c,VIId,e North Sea and English Channel 180 170 220 180 750 IIIa-d Baltic, Skagerrak and Kattegat 270 250 140 160 810 Vb,VIa,b,f,g,j Faeroes and W. UK 190 220 290 240 950 VIIIa-c,IXa,X France, Iberia, Azores 40 20 30 20 110 Total 1340 1490 1940 1580 6350 Table 5.9. Approximate food consumption (tonnes x 1000) by seabirds occupying NAFO areas in winter, spring, summer, and autumn. NAFO areas Winter Spring Summer Autumn Total 0 Eastern Baffin Island 0 100 130 60 300 1 West Greenland 230 670 1110 230 2240 2 and 3 East NFL and Labrador 730 230 180 800 1940 4 Gulf of St. Lawrence and Scotian Shelf 50 70 80 60 250 5 Gulf of Maine 20 75 100 40 230 6 Long Island to Cap Hatteras 40 50 60 60 200 Total 1070 1190 1650 1260 5160 5.2.4 Comparison to earlier models Seasonal movements. Taking seasonal movements of birds between NAFO and ICES areas into account increased the original estimate of food consumption in the ICES areas (ICES 2002) by 17% (from 5.4 to 6.3 mill. tonnes) and in the NAFO areas by 75% (from 2.9 to 5.2 mill. tonnes) (Table 5.10). In the ICES areas this is most evident in ICES IIIa-d (Baltic, Skagerrak and Kattegat) where taking into account the population of wintering seaducks doubled the annual consumption estimate for that subarea. The most striking differences in the NAFO areas are due to the huge seasonal influxes of birds from the southern oceans (into NAFO 5 and 6), northern ICES areas and the eastern Canadian Arctic (into NAFO 2 and 3) mentioned above. ICES WGSE Report 2004 25
Page 1 and 2: ICES Oceanography Committee ICES CM
Page 3 and 4: Contents 1 Introduction............
Page 5 and 6: 1 INTRODUCTION 1.1 Participation Th
Page 7 and 8: egion, but its size and importance
Page 9 and 10: addition, mass mortality events on
Page 11 and 12: During autumn migration surprisingl
Page 13 and 14: Table 3.4.1. Score of the nine vuln
Page 15 and 16: It might be considered useful to di
Page 17 and 18: performance and climatic variables,
Page 19 and 20: Calculation of numbers of birds in
Page 21 and 22: Table 5.1. Relative species composi
Page 23: Table 5.4. Approximate numbers of s
Page 27 and 28: Kershaw, M., and Cranswick, P.A. 20
Page 29 and 30: 6 CONSUMPTION OF PREY BY SEABIRDS I
Page 31 and 32: WGSE and ACE recommended in 2003 (I
Page 33 and 34: The present level is that around 60
Page 35 and 36: Kittiwake breeding success at Foula
Page 37 and 38: 7.7 Seabird population trends as an
Page 39 and 40: 8.2.1 UK (ICES IVa-c) Data on popul
Page 41 and 42: Table 8.2. Some breeding population
Page 43 and 44: Table 8.4. Some breeding population
Page 45 and 46: Table 8.5. Continued. HUNTING STATU
Page 47 and 48: Norwegian Institute for Nature Rese
Page 49 and 50: 10 ANNEXES Annex 1 List of particip
Page 51 and 52: Relation to strategic plan: Resourc
Page 53: English name Scientific name Goosan

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