Lipid classes and fatty acid compositions of muscle, liver and skull oil in deep‐sea redfish Sebastes mentella over the Reykjanes Ridge

Abstract

The fatty acid profiles of neutral and polar lipids were analysed in tissues of muscle, liver and skull oil of the deep‐sea redfish Sebastes mentella caught over the Reykjanes Ridge. The fatty acid compositions of both the neutral and the polar lipid fractions were tissue specific. The high amounts of the phytoplankton‐derived fatty acids, 20:5n3 and 22:6n3, in the neutral fractions of the muscle tissues clearly distinguished the muscle lipids from liver lipids and skull oil. In the skull oil, the fatty acid profiles of the neutral lipids were characterized by extremely high amounts of the long‐chained mono‐unsaturated fatty acids, 22:1n1, 20:1n9 and 18:1n9, indicating selective enrichment of these fatty acids. Of the tissues studied here, the neutral fraction of the muscle best reflects diet, while the skull oil is believed to be unsuitable in trophic studies. Interestingly, in the muscle oil, there were high amounts of docosahexaenoic acid, 22:6n3 (23%). Docosahexaenoic acid is a unique fatty acid important in the cell membrane, and the levels found in S. mentella are similar to those found in other deep‐living fish species.