Estuarine Ecology of Juvenile Salmon in Western Alaska: a Review

摘要: —In the late 1990s and early 2000s, large declines in numbers of chum salmon Oncorhynchus keta Chinook O. tshawytscha returning to Arctic-YukonKuskokwim (AYK) region (Alaska, USA) illuminated need for an improved understanding variables controlling abundance at all life stages. In addressing questions about abundance, gaps our knowledge basic history critical marine stage were revealed. this paper, results from studies conducted on estuarine ecology juvenile western Alaska are summarized compared, emphasizing timing distribution during outmigration, environmental conditions, age growth, feeding, energy content smolts. Alaska, water temperature dramatically changes with season, ranging 0°C after ice melt spring/early summer 19°C July. Juvenile found AYK estuaries May until August or September, but date no information is available their residence duration survival probability. Chum most abundant reported, percent catch <0.1% 4.7% research effort has focused species. Abundances salmon, sockeye nerka, pink gorbuscha varied among estuaries, while coho kisutch juveniles consistently rare, never amounting more than 0.8% catch. Dietary composition was highly variable a shift commonly reported epibenthic neustonic prey lower salinity pelagic higher water. Gaps still evident. For example, data outmigration patterns duration, rearing conditions effect diet, often completely lacking only few selected years sites. Filling concerning use near-shore habitats within will aid assessing relative roles (freshwater marine) abundance. 184 Hillgruber Zimmerman