Distribution and General Biological Features of Snow Crab (Chionoecetes opilio) in the Chukchi and East Siberian Seas

— Hydrobiological surveys (plankton and benthos, including snow crab) were carried out in the southwestern region of the Chukchi Sea in the summer of 2003–2020. At the western, eastern, and northern edges of C. opilio distribution area in the Chukchi Sea, the abundance of crabs was five to ten times lower due to the limit of the species tolerance to hydrological factors and shortage of food resources, low mass of zoobenthos. Aggregations of snow crab C. opilio in northern regions of the Chukchi and the East Siberian seas can be considered dependent on replenishment from southern regions of the Chukchi Sea. The southern regions of the Chukchi Sea are some kinds of the nursery for development and growth of snow crab larvae and juveniles until 1–2 years age, from where they migrate into northern deeper regions of the Chukchi Sea, and then farther to the northeastern region of the East-Siberian Sea.