Some aspects of the feeding biology of larval walleye pollock, Theragra Chalcogramma (Pallas), in the Southeastern Bering Sea: a thesis

Abstract

The purpose of this study was to determine which organisms are the major food items for larval walleye pollock, Theragra chalcogramma, in the southeastern Bering Sea. The gut contents of 697 larval walleye pollock collected in the southeastern Bering Sea were examined. The larvae ranged in size from 4.8 mm to 17.7 mm. All food items were identified to taxa as far as condition would allow. The width of all intact food items was measured. Copepod nauplii and eggs composed the largest portion of the food items taken by the smallest larvae. As the size of the larvae increased, greater numbers of larger food such as copepods were taken. Oithona similis was the most common copepod ingested. Feeding incidences were 100% for size groups 7.8-8.7 mm and longer and varied considerably for size groups 6.8-7.7 mm and smaller. This may indicate that food availability is limiting only for larvae 7.7 mm and smaller.