The effect of environmental temperature on the fatty acid composition of crustacean plankton

Measurements of the iodine value made over a period of three years demonstrate a regular yearly cycle in the composition of the fat of crustacean plankton in Lake Balaton. The melting point of the lipid of the planktonic copepods remained during the whole year somewhat lower than the water temperature. The proportions of the C20–C22 poly-unsaturated acids in the planktonic crustaceans increased with decreasing temperature and in some species exceeded the values characteristic of marine animals. In fresh-water fish, kept at room temperature and fed on freshly collected fresh-water plankton, the lipids formed in winter resembled marine fish oil.In the crustaceans raised on algae containing no fatty acids longer than C18, the C20-C22 acids always appeared as major components of the copepods.