Fatty Acid Composition of Juvenile Pink Salmon Oncorhynchus gorbuscha during Downstream Migration from the River Indera to the White Sea.

The fatty acid (FA) composition was studied in pink salmon smolts during their migration (from start to ending) in the Indera River and in an experiment with stationary cages (in the river, the estuary, and the White Sea), taking account of differences in water temperature and salinity. Changes in the quantitative composition of FAs (higher contents of total saturated (SFAs) and monounsaturated (MUFAs) FAs and a lower content of polyunsaturated FAs (PUFAs)) were found in smolts in the middle of their downstream migration and in an experimental group kept in cages in the sea for 72 h. The qualitative composition of major FAs (16:0, 18:1(n-9), 20:5(n-3), and 22:6(n-3)) was the same in all of the study groups and was similar to that at earlier stages of pink salmon development. Variations in the contents of 20:5(n-3) and 22:6(n-3) were observed in experimental smolt groups that confirmed the important role of these PUFAs in adaptation of pink salmon smolts to the transition from a freshwater river ecosystem to living in the sea.