Comparison of Feeding Pattern of Pacific Salmon between the Western Subarctic Gyre and the Gulf of Alaska in Summer 2005

摘要

Pacific salmon (Oncorhynchus spp.) is one of the keystone species in the North Pacific Ocean ecosystem. Their feeding ecology is influenced by the oceanic environment such as ENSO event (Kaeriyama et al. 2000, 2004), inter- and intra-specific interaction such as density-dependent effect (Tadokoro et al. 1996; Kaeriyama et al. 2000, 2004; Ruggerone et al. 2003), and also population dynamics of prey animal community (Shiomoto et al. 1997), because salmon are opportunistic feeders (Kaeriyama et al. 2000). The evalutation of feeding ecology of Pacific salmon is useful for understanding on prey-animal community structure in the North Pacific Ocean. In this study, we examined the feeding pattern of Pacific salmon in the Western Subarctic Gyre (WSG) and the western Gulf of Alaska (GA) in summer 2005 to understand their feeding ecology.