Food Supply and Trophic Relationships of Pacific Salmon (Oncorhynchus spp.) and Atka Mackerel (Pleurogrammus monopterygius) in the Western Bering Sea in Fall 2002-2004

摘要

We examined the food supply and trophic relationships of pink (Oncorhynchus gorbuscha), chum (O. keta) and sockeye (O. nerka) salmon and juvenile Atka mackerel (Pleurogrammus monopterygius). We studied interannual variability in feeding habits, zooplankton prey fields, diel feeding chronology and diet overlap in the deepwater regions of the western Bering Sea in September-October, 2002-2004. Pacific salmon and Atka mackerel fed primarily on zooplankton. Most of their diets consisted of few food items. All fish showed similar diel feeding rhythms and consumed food mostly during the day. Diet overlaps were high for small- and medium-size salmon and moderate for large salmon. We conclude there was a low potential for feeding competition among major salmon species and juvenile Atka mackerel in the western Bering Sea in fall 2002-2004.