Stock dynamics of walleye pollock in the Okhotsk Sea in connection with their long-term habitat changes
A combined data analysis on sea ice as the integral index of the Okhotsk Sea hydrologic regime and the long-term stock dynamics of walleye pollock has shown that these data agree in their variations. The high-level stock occurred in the low-sea-ice years or close-to-mid-sea-ice, and on the contrary, the low-level stock occurred in the high-sea-ice years. During the cold high-sea-ice years, a species survival is lower than in warm years, which are more often low-sea-ice. The conclusion is that the nursery layer formation for a new year class after spawning is significantly disturbed in the cold years, and this causes a decline in survival and, finally, in species abundance.