FATTY ACIDS OF SOME MARINE CRUSTACEANS

The lipids of one species of epipelagic euphausiid and six species of mesopelagic decapods from the eastern-North Atlantic have been shown by thin-layer chromatography to consist mainly of triglyceride, with small amounts of mono- and di-glyceride, sterol, sterol ester and phospholipid. The generally low level of lipid (2-5% wet weight) suggests that lipids have no buoyancy function in these animals. Gas-liquid chromatography showed that the fatty acid composition of Euphausia brevis differed from that of the decapods in having much less octadecaenoic acid (18:1) and more eicosapentaenoic acid (20:5) and docosahexaenoic acid (22:6). The principal differences in the fatty acid composition of the decapods were in their contents of octadecaenoic, eicosaenoic (20:1) and docosaenoic (22:1) acids, but no correlation was found between fatty acid composition and species. A specimen of Acanthephyra acanthitelsonis which had a high fat content (9% wet weight) had a fatty acid composition different from that of another specimen with a normal fat content (3·8%). No significant differences were found between samples of Systellaspis debilis collected from two stations 1000 miles apart. © 1969.