Comparative characteristics of food supply of Pacific salmon (Oncorhynchus spp.) in the Bering Sea from 2002 to 2006

Abstract

Based on complex epipelagic surveys in the western Bering Sea, a comparative analysis of food supply of Pacific salmon (Oncorhynchus spp.) was conducted in summer and fall from 2002 to 2006. Nine indirect indices of food supply used in the study were as follows: feeding similarity, width of the feeding spectrum, diet feeding ration, diet feeding rhythms, fraction of accessory food in the ration, growth rate of the fish, abundance of food resources, and abundance of salmon. The food supply of salmon is lower in summer 2003 and fall 2006 in comparison to the food supply in other years of the study. However, well expressed feeding selectivity, consumption of prey items of certain type, and small proportion of accessory food (copepods and chaetognaths) prevailed in plankton, suggests the presence of sufficient food resources for Pacific salmon in the western Bering Sea.