Depot fatty acid composition in immature green turtles(Chelonia mydas)residing at two near-shore foraging areas in the Hawaiian Islands

摘要

The lipid content and fatty acid composition of depot fat were determined for 58 immature green turtles(Chelonia mydas)residing at two near-shore foraging areas,Ahu-O-Laka,located in Kaneohe Bay on Oahu,and Kiholo Bay located on the island of Hawaii.Benthic flora at Kiholo was limited to a single algal species but included algae and seagrass at Ahu-O-Laka.Turtle straight carapace length ranged from 38.6 to 59.2 cm,suggesting that the sample set included new recruits to up to 12-year residents.Fatty acid data were analyzed using principal components analysis(PCA).PCI accounted for over 50% of the variance.Turtles were generally delineated along PC1 by the length of time on benthic foraging grounds,with high(>0.75)negative loadings for the fatty acids 22:6n-3,7M7H,t 16:ln-10,15:0,and 17:0 associated with relatively new recruits(suggesting a pelagic dietary source for these fatty acids)and high positive loadings for 12:0 and 14:0 associated with long-term residents.PC2 separated turtles primarily by capture location,with high positive loadings for 18:2n-6 and 18:3n-3[the primary seagrass polyunsaturated fatty acids]associated with the Ahu-O-Laka turtles.Fatty acid profiles of turtles from both locations differed substantially from those of their benthic diets,suggesting considerable modification of dietary fatty acids and de novo biosynthesis.