The Sea of Okhotsk is a continental margin water body of 1.6 million km2. The average depth is 891 meters, and the maximum depth is 3,916 m. (Leonov, 1960; Dubrovolsky and Zalogin, 1982) Generally the sea is shallow to the north and deep to the south.(Udintsev, 1957) The climate is temperate, but because of the large area, there are marked differences in climate, hydrography, and biology from north to south. Surface temperatures range from -1.5 to -1.8 C. in the winter to 11-13 degrees C. (except off Hokkaido Island, where it is 19 degrees C.) Below 30-75 meters, the water temperature is persistently cold, approximately -1.7 degrees C. (Kuznetsov, et al., 1993). The current system is complicated, with three large cyclonic gyres as part of the sea. (Chernyavsky, 1981) The Sea is connected to the northern Pacific Ocean through straits at the southern end of the Kuril Islands, through which water exits to the Pacific. At the northern end of the Kuril Islands, Pacific waters enter the Sea. (Kuznetsov, et al, 1993) The climate and hydrography are highly variable, related to atmospheric processes over the northwest Pacific, which affect heat advection via currents flowing into the Sea of Okhotsk in the northern Kuril Island straits. (Davydov, 1984) Overfishing has affected two to three of the major fish stocks. Fishery management programs have resulted in an increase and stabilization of demersal stocks, and moderate fishing of walleye pollock may be sustainable (http://www.na.nmfs.gov/lme/text/lme52.htm; formerly Sea of Okhotsk).