Winter Ecology of Pacific Salmon

Abstract Excerpt:
Winter is a highly important time in Pacific salmon (Oncorhynchus spp.) marine life, first, due to its duration. If we consider winter to be the four months from December to March in the latitude range of Pacific salmon ocean migration, it makes up from one-third to one half of the ocean residence time for pink O. gorbuscha and coho O. kisutch salmon originated from the marginal seas’ basins. Some researchers consider winter as a critical period for Pacific salmon, likely due to a general feeling of inconvenience and danger associated with the stormy ocean environment, low water temperatures, significant decreases in forage fish and zooplankton biomasses in the upper pelagic layer that imply limited food availability. Physiological studies revealed salmon growth slowing and lowering of muscle lipid content (Naydenko et al. 2016).