The zooplankton community of the Barents Sea consists mainly of typical phytophages feeding on phytoplankton. However, there are also representatives of predatory plankton including Chaetognatha, most Amphipoda (Hyperiidae), Pteropoda, and also “jellyfish” – Scyphozoa (genus Aurelia, Cyanea) and Ctenophora. Large-scale predation of Calanus by ctenophores was observed in the Barents Sea in 1971 and 1983 (Fomin, 1985). Chaetognatha prefer rather large prey, such as small and large Copepoda, Cirripedia larvae, Euphausiacea and their larvae, also Amphipoda, fry of Chaetognatha and Oikopleura.
The preferred prey stocks of seabirds have undergone large variations the last decades, either because of overfishing or other variation in the ecosystem. The variation in capelin biomass is for example described above. These large fluctuations have had consequences for some species resulting in either serious declines in e.g. common guillemot, Brünnich’s guillemot and puffin breeding populations,...
The Barents Sea is strongly influenced by human activities. Historically, this involves fishing and hunting of marine mammals. More recently, human activities also involve transportation of goods, oil and gas activities, tourism and aquaculture. This chapter focus mainly on impact from human activities that occur today in the Barents Sea. Past harvest of populations which have had a lasting impact...
