The red king crab (Paralithodes camtschaticus) was deliberately introduced to the Barents Sea at several locations during the 1960s and 1970s from the northern part of the Pacific (Olav and Ivanovo, 1978). It has continuously spread to new areas and is now distributed from the Kluge Island to east, the Goose Bank to north, and west to Lofoten and Kvænangen to west along the Norwegian coast. The expansion of the area inhabited by red-king crabs occurred during years when water temperature in Atlantic currents was higher than normal (Pinchukov and Karsakov, in press). Several studies have revealed that the crab besides being an important fishing resource, also significantly impact the bottom ecosystem in areas of high densities of crabs (Sundet and Berenboim, 2008).
In Russian waters of the Barents Sea, red-king crabs occur in areas from shallow waters to the depths below 335 m, at the temperature range from -0,8 to +8,5º С. In spring, April-May, they form spawning aggregations of individuals of both sexes within temperature range 0-2º С. In autumn, August-September, red-king crabs form separate aggregations where males aggregate in concentrations within the temperature range 4-6º С and females within 5-7º С. The individual fecundity varies from 70,000 to 700,000 eggs. The average fecundity is 250,000 eggs (Bakanev, 2003). The maximum known size is 270 mm carapax length, and weight is 7.4 kg. Red-king crabs are benthophage predators (Gerasimova and Kachanov, 1997; Manushin, 2003), but in areas with intensive fishing, they predominantly feed on fish offal (Pinchukov and Pavlov, 2002; Anisimova and Manushin, 2003). The main red-king crab predators in the Barents Sea are cod, wolffish and skates (Matyshkin, 2001).