The Role of Kelp in the Marine Environment - National Parks ...

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Laridae (Gulls) e.g., Herring Gull Larus argentatus. Sternidae (Terns) e.g., Common Tern Sterna hirundo. Alcidae (Auks) e.g., Common Guillemot Uria aalge. Members of the Gaviidae family that occur within inshore waters include the scarce Red Throated Diver Gavia stellata and Black Throated Diver Gavia arctica. The Great Northern Diver Gavia immer is the most numerous diver species off the Irish coast during winter (Colhoun, 2001). There are no substantiated links between any of these diver species and rocky reef and kelp habitats. Principal prey items include Cod Gadus morhua, Herring Clupea harengus and Sprats Sprattus sprattus and sandy bays appear to be the most preferred winter habitat in Ireland (e.g., Lack, 1986) although Ferns (1992) suggests that Great Northern Divers in Britain are more strongly associated with rocky coastlines. Great Crested Grebes Podiceps cristatus occur in a variety of inland and coastal aquatic habitats and there appears to be no significant link between their distribution or foraging behaviour and kelp forests. Members of the Phalacrocoracidae family include two piscivorous seabirds: Cormorant Phalacrocorax carbo and Shag Phalacrocorax aristotelis. Cormorants and Shags occur in Ireland during the breeding and non-breeding season and nest within colonies on cliffs, stacks and other rocky areas. Coastal breeding populations of Cormorants within Ireland are currently considered to be stable. In contrast, the number of Shags in Ireland has declined by 27% since the Seabird Colony Register census of 1985-1988 (Sellers, 2004). Both species are widely distributed in varying sized breeding colonies around the Irish coastline where suitable habitat exists. Cormorants forage within shallow inshore marine waters (e.g., Lack, 1986; Johansen et al., 2001). Previous studies have identified a connection between kelp forests, fish and Cormorants. For example, a relationship was found between the feeding areas of breeding Cormorants (Phalacrocorax carbo) and kelp forests within their feeding range (Røv et al., 1990). In Norway, Cormorants and Shags (P. aristotelis) prey upon large numbers of gadoid fish (Barrett et al., 1990) and kelp forests of Laminaria hyperborea are important habitats for juvenile gadoids (Sjøtun & Lorentsen, 2003). 35
The reported decrease of Cod Gadus morhua in the diet of Cormorants probably reflects the decrease in the Norwegian Cod population (Lorentsen et al., 2004) that in turn is linked to kelp harvesting and its negative effects on juvenile recruitment (Sjøtun & Lorentsen, 2003). However, there is no current evidence that Cormorant populations are in decline due to kelp harvesting, although longer-term population studies will be useful to monitor the effects of kelp harvesting (Lorentsen et al., 2004) No clear relationship between Shags and kelp forests have been previously described. Sandeels Ammodytes marinus are a favoured prey item and these are thought to occur predominantly on sandy or gravel substrata (Wanless et al., 1997), also the nursery grounds of this fish species. While Shags feed in deeper waters than Cormorants (21- 40m: Wanless et al., 1991) they also occur in areas of shallow rocky coast and prey upon fish and crustaceans (Cramp & Simmons, 1977; Ferns, 1992). Further, Sandeels have been recorded within Norwegian kelp forests (Hoeiaseter & Fossaa, 1993). Interactions between Shags and kelp forests are therefore likely. Members of Anatidae family that may feed within kelp forests along Irish coasts are seaducks such as the Common Eider Somateria mollissima, Common Scoters Melanitta nigra and Red Breasted Merganser Mergus serrator, all of which feed in inshore waters particularly at low tide when the bottom is easier to reach (Ferns, 1992). Sea ducks are thought to prefer rocky substratum communities that are often dominated by vegetation such as kelp (Bustnes & Systad, 2001a). In particular, the rare Steller’s Eider Polysticta stelleri (not found in Ireland) is noted to prefer foraging within kelp forests (Laminaria hyperborea) of northern Norway although kelp distribution alone, cannot explain the distribution of this wintering seaduck (Bustnes & Systad, 2001b). The Irish breeding distribution of Common Eider extends westwards around the coastline from the Copeland Islands, Co. Down to Inishmurray in Co. Sligo with some additional nest locations recorded e.g., Inishkeeragh, Co. Mayo (Murray & Cabot, 2002). Common Eiders feed predominantly on molluscs and crustaceans but will also prey upon crabs and starfish (Lack, 1986; Ferns, 1992). Common Scoters will feed upon crustaceans and gobies and similar to the Red Breasted Merganser, are not solely restricted to rocky reef areas. 36
Page 1: The Role of Kelp in the Marine Envi
Page 4 and 5: Details of Contributors Birds Fish
Page 6 and 7: Executive Summary Kelp forests have
Page 8 and 9: Birds Acknowledgements Professor R.
Page 10 and 11: Introduction Kelp species represent
Page 12 and 13: Each year the kelp plant renews its
Page 14 and 15: estimate (Birkett et al., 1998) of
Page 16 and 17: Other researchers have highlighted
Page 18 and 19: Figure 2 δ 13 C values from the di
Page 20 and 21: kelp population was estimated by Ar
Page 22 and 23: Figure 4 Growth in length of the la
Page 24 and 25: varies with the age of the plants.
Page 26 and 27: Table 3 Primary production as tonne
Page 28 and 29: accuracy. Most epiphytic algae are
Page 30 and 31: collected off the Cumbrian coast ri
Page 32 and 33: Lavery et al. (1999) and Dugan et a
Page 34 and 35: (op. cit.) and Lorentsen et al. (op
Page 38 and 39: Interesting studies of the interact
Page 40 and 41: 1985). These birds prey upon e.g. b
Page 42 and 43: as amphipods and crabs beneath. Pur
Page 44 and 45: An interesting and indirect interac
Page 46 and 47: 5-8% lower than velocities above th
Page 48 and 49: Methods of Kelp Harvesting Impact R
Page 50 and 51: Scale of kelp removal It is self ev
Page 52 and 53: Blade cutting vs. complete plant re
Page 54 and 55: � fallow years, as successfully p
Page 56 and 57: trophic and habitat associations (N
Page 58 and 59: Foreman (1984) noted that if sustai
Page 60 and 61: variability in benthic community st
Page 62 and 63: lock was occupied by laminarians an
Page 64 and 65: Laminaria hyperborea (Gunn.) Foslie
Page 66 and 67: Pylophora crispa, 1% Ceramium nodul
Page 68 and 69: Most species on L. digitata were en
Page 70 and 71: after 3 days exposure in September
Page 72 and 73: many species have planktonic larvae
Page 74 and 75: decline in juvenile rockfishe, i.e.
Page 76 and 77: Species classified as threatened or
Page 78 and 79: The conservation status of bird spe
Page 80 and 81: Production Future Research Nearly a
Page 82 and 83: � Biomass and standing stock surv
Page 84 and 85: legislative obligations in relation
Page 86 and 87:
Conclusions Even well managed kelp
Page 88 and 89:
waters and with the postulated rise
Page 90 and 91:
Arzel, P. (1998). Les laminaires su
Page 92 and 93:
Bustamante, R. H. & Branch, G. M. (
Page 94 and 95:
Christie, H., Jorgensen, N.M., Nord
Page 96 and 97:
Deady, S. and Fives, J.M. (1995b).
Page 98 and 99:
ecosystems. Bulletin of Marine Scie
Page 100 and 101:
Graham, M. H. (2002). Prolonged rep
Page 102 and 103:
Kain, J. M. (1977). The Biology of
Page 104 and 105:
Mann, K. H. (1988). Production and
Page 106 and 107:
Nicholson, N.L. (1970). Field studi
Page 108 and 109:
Quast, J. C. (1968a). Fish fauna of
Page 110 and 111:
Sellers, R. M. (2004). The Great Co
Page 112 and 113:
Swaby, S.E. and Potts, G.W. (1990).
Page 114 and 115:
Went, A. E. J. (1957). List of Iris
Page 116 and 117:
Appendix 2 Macroinvertebrate specie
Page 118 and 119:
Gibbula umbilicalis Helcion pelluci
Page 120 and 121:
Appendix 3 Description of habitat,
Page 122 and 123:
Appendix 3 continued Anguilla angui
Page 124:
Appendix 4 Conservation status of b
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