Fatty Acid Profiles in the Gonads of Red King Crab (Paralithodes camtschaticus) from the Barents Sea

SIMPLE SUMMARY: Invasive red king crabs support a large-scale fishery in the Barents Sea, but, currently, their by-products are not used by the food and pharmaceutical industries, partly because information regarding the biochemical content of the by-products is scarce or absent. For this reason, we assayed fatty acid profiles in the ovaries and testes of adult red king crabs. We found a predominance of polyunsaturated fatty acids and lower levels of saturated and monounsaturated fatty acids. Female gonads showed higher levels of fatty acids than male gonads due to higher levels of energy allocation to reproduction processes in females, which have larger and heavier gonads but smaller and lighter bodies than males. Ovaries are characterized by excellent quality in terms of the high content of essential fatty acids and could be recommended for consumption and as a source of valuable substances. ABSTRACT: Red king crab (Paralithodes camtschaticus) is a large shelf species native to the Pacific Ocean. Due to its high commercial value, this species was introduced into the Barents Sea, where it has formed a new population that now supports a stable commercial fishery. Information on fatty acid profiles in different tissues of the Barents Sea P. camtschaticus is scarce. For this reason, the gonads of red king crabs collected at a coastal site in the Barents Sea during the summer were analyzed for fatty acid composition by gas-liquid chromatography. The proportions of total saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids in the ovaries of P. camtschaticus were 25.9 ± 2.0%, 22.5 ± 2.3%, and 51.6 ± 2.5%, respectively; in the testes, these levels accounted for 35.1 ± 5.7%, 19.1 ± 2.0%, and 45.8 ± 4.5%, respectively. Fatty acid profiles were similar in larger and smaller red king crabs and crabs with old and new shells. Concentrations of fatty acids were higher in ovaries compared to testes, reflecting higher reproductive efforts in female red king crabs. High levels of docosahexaenoic and eicosapentaenoic fatty acids detected in the ovaries of red king crabs from the Barents Sea indicate that these gonads can be a good alternative source for these fatty acids in the human diet and/or for extracting important fatty acids for use in the medical and pharmaceutical industries.