Liver lipids of Indian and Atlantic Ocean spinner Carcharhinus brevipinna and blacktip Carcharhinus limbatus sharks

Abstract

Shark liver oils are rich in polyunsaturated fatty acids, especially the n3 moieties. Data on the liver fatty acids of sharks from African waters, however, are limited. Liver samples from sharks from the western Indian Ocean off the east coast of South Africa and those from the Atlantic Ocean and Gulf of Mexico were examined. This study reports on the fatty acids found in the total lipid fractions from the livers of two shark species found in these regions, the spinner Carcharhinus brevipinna and blacktip Carcharhinus limbatus. Greater amounts of total lipids were found in sharks from the Indian Ocean than in those from the Atlantic Ocean (spinner 0.431 g g⁻¹ vs 0.324 g g⁻¹, p = 0.004; blacktip 0.426 g g⁻¹ vs 0.261 g g⁻¹, p = 0.004). The individual fatty acids in the same animals showed reduced amounts of saturates (spinner 26.22% vs 30.68%, p = 0.013; blacktip 28.94% vs 35.14%, p = 0.007) and slightly increased n3 polyunsaturates (spinner 33.67% vs 22.89%, p = 0.001; blacktip 24.77% vs 18.68%, p = 0.025). Generally, the geographical location rather than the shark species was most important in determining the proportions of hepatic lipids.