Changes in Lipids of Young and Adult Saury Cololabis saira (Pisces)

Abstract

Class and fatty acid compositions of the lipids were investigated in young and adult saury Cololabis saira from the northwestern Pacific Ocean. In the flesh of young fish during northward migration, lipid contents were about 3 O/O. Adults in the feeding period contained more than 15 O/o lipid contents in August (males) and September (females). In adult flesh, the lipid contents decreased gradually during southward migration and reached about 4 O/O in late November. Triglycerides in flesh lipids increased with lipid accumulation. Wax esters occurred mainly as a minor component in flesh lipids of saury during the feeding period. Fatty acids of adult non-polar lipids contained more 20:l and 22:l than those of juveniles. These acids increased gradually during southward migration and reached 24.7 '/a for 20:l and 32.8 O/O for 22:l in late November. On the other hand, 16:0, 16:l. 18:l and 18:4w3 tended to decrease. These fluctuations in lipd may be related not only to dietary lipids but also to the utilization of lipids by the fish for migration and gonadal maturation.