The effects of water temperature on the seasonal distribution and growth of walleye pollock, Theragra chalcogramma (Pallas), in the southeast Bering Sea

Abstract

The distribution and growth of walleye pollock, Theragva ohalaogvamna (Pallas), were studied in relation to bottom water temperatures, in an area between latitude 54°30'N and 57°30'N and longitude 160°W and 170°W, from the data collected from 1976 to 1980. The annual variations of bottom temperature distribution, including mean temperature, are described. It is found that temperature boundaries regulate spawning aggregation areas and feeding distribution of adult pollock. Young pollock were distributed in a wider temperature range and revealed a clearer feeding migration pattern than the adults. The weight growth for walleye pollock aged 2 to 4 was determined. The growth rate varied with age, sex and year. The relative growth rate was related to the initial weight of the fish and the mean temperature. Additional seasonal variations in the length-weight relationship and condition factor were observed.