Lipid content in the young-of-the-year sockeye salmon Oncorhynchus nerka during feeding migration (the Ozernaya River, Western Kamchatka).

摘要

Sockeye salmon Oncorhynchus nerka of Kam chatka populations in comparison to other Pacific salmon differs in that it spends its freshwater period predominantly in lakes. Spawning grounds of sockeye salmon are situated both in lakes and in rivers flowing in or out of the lakes. Therefore, to reach a rearing lake juvenile sockeye salmon perform differently directed migrations as soon as in the first year of life. The direc tion of migrations depends on the location of spawn ing areas relative to the rearing lake. Before the escape to the lake youngoftheyear sockeye salmon accu mulate in the river source in the zone of reverse flow [5, 6]. Along with mass upstream migration, down stream migration occurs in rivers flowing out of lakes [6, 7, 13].