Source, density and composition of sympagic fauna in the Barents Sea

Abstract

The sympagic fauna (= ice fauna) of the Barents Sea was investigated on nine different cruises in 1982-1988. Each cruise lasted from two to five weeks. Sampling techniques were based on scuba diving. The abundant sympagic organisms were the polar cod (Boreogadus saida) and the three amphipods Apherusa glacialis, Onisimus sp. and Gammarus wilkitzkii. Mean biomass-values (wet weight) of the invertebrate sympagic fauna ranged from 0 to 2 g/m2. Values above 0.001 g/m2 were not recorded in five of the nine cruises. This is orders of magnitude lower than mean values recorded in multi-year ice north of Svalbard and in the Fram Strait where values between 1-10g/m2 are quite common. Apherusa glacialis seemed to have the best spreading capacity of the three most conspicuous amphipods. Gammarus wilkitzkii was most dependent on a passive transport with the ice. Sympagic amphipods play an important part in a food chain from microalgae to polar cod and marine birds in areas covered with ice, especially in areas with multi-year ice.