Effect from the king- and snow crab on Barents Sea benthos. Results and conclusions from the Norwegian-Russian Workshop in Tromsø 2010

Abstract

The king crab move further out in the sea in Russian waters compared to the Norwegian waters. This might have important implications on the distribution of feeding pressure and impact of crabs on benthic communities making them different in different areas. Though the king crab population is still spreading along the coast, the snow-crab population, spreading on the seafloor of the open sea, is expected to increase beyond the standing stock of king crab. The king crab has a measurable effect from foraging on large visible sea stars, brittle stars and bivalves and preferable prey will decrease while species, not preferred, will become dominant together with “hide or flight” bottom animals. Some areas show sign of almost extinction of large prey, and borrowing fauna inside the sediment might have decreased due to the foraging from the crab, and consequently left the sediment environment low in oxygen. Areas with refuge still have high biodiversity.