Arctic Cod in the Russian Arctic: New Data, With Notes on Intraspecific Forms

Abstract

The Polar cod Boreogadus saida, from Siberian shelf is largely unstudied. Comparative results are presented for the Barents, Pechora, Kara, Laptev and East-Siberian seas. Surveys included 325 bottom catches, 234 pelagic and 72 Sigs by trawls at 385 stations. It is quantitatively confirmed that B.saida dominates in arctic areas. The maximum length is 29.0 cm and age 7+ (Laptev Sea). It prefers temperatures in the range -1.8 to +2.3° C. Polar cod is represented by several intraspecific forms differing in proportions of body, size and position of fins and in coloration. It remains a mystery in what places the spawning of this fish occurs in the Arctic. A hypothesis is proposed that B.saida spawns in a system of winter quasi stationary polynya which may extend from the White Sea to the Chukchi Sea along the edge of fast ice. The local regimes of their functioning create the preconditions for existing of a number of stocks or populations within circumpolar range.