INTERACTIONS AMONG MARINE BIRDS AND COMMERCIAL FISH 



203 



Routes of Interaction 



Between Marine Birds and 



Commercial Fish 



The obvious ways in which marine birds and 

 fish of commercial importance interact in the 

 eastern Bering Sea are illustrated by the sim- 

 plified food web diagram in Fig. 4. The major 

 animal groups and species included in two of 

 the categories in this figure secondary pro- 

 ducers (invertebrate forage) and intermediate 

 carnivores (commercial and forage marine fish 

 and shellfish) are as follows: 



Secondary producers 



Zooplankton and micronekton 

 Copepods 

 Calanus spp. 

 Eucalanus spp. 



Euphausiids 

 Thysanoessa spp. 



Amphipods 

 Parathemisto spp. 

 Gammarus spp. 



Pteropods 

 Spiratella spp. 

 Clione spp. 



Chaetognaths 

 Sagitta spp. 



Benthos 

 Polychaetes 

 Nereis spp. 

 Euroe spp. 



Molluscs 

 Mytilus edulis 

 Tonicella spp. 

 Fusitriton oregonensis 



Echinodermata 

 Strongylocentrotus spp. 



Crustacea 

 Gammaridae 

 Mysidae 

 Idothea spp. 

 Pagurus spp. 

 Hapalogaster spp. 

 Sclerocrangon spp. 



Fig. 4. Food web in the eastern Bering Sea, showing 

 routes of interaction between marine birds and 

 the various life history stages of commercial fish 

 and shellfish. 



Intermediate carnivores 



Eggs (littoral, adhesive) 

 Clupeidae 



Pelagic larvae 

 Gadidae 

 Pleuronectidae 

 Osmeridae 

 Ammodytidae 

 Salmonidae 

 Gadidae 

 Pandalidae 



Juvenile and small adults 

 Clupeidae 

 Osmeridae 

 Ammodytidae 

 Salmonidae 

 Gadidae 

 Pandalidae 



Large adults 

 Clupeidae 

 Gadidae 

 Pleuronectidae 

 Salmonidae 

 Scorpaenidae 

 Lithodidae 

 Majiidae 

 Pandalidae 



Marine birds 

 Alcidae 

 Procellariidae 

 Laridae 

 Phalacrocoracidae 



