Comparison of the fatty acids in Baltic herring and available plankton feed.

Triglycerides and phospholipids dominate in Baltic herring flesh lipids throughout the plankton growth season though at the same time plankton species and their lipids vary considerably. Wax esters and fatty alcohols do not exist in significant amounts in Baltic herring flesh or plankton. Saturated fatty acids exist in equal proportions in herring and plankton lipids whereas monoenoic acids are more dominant in herring and polyunsaturated acids in plankton lipids, respectively. The component alkyl chains are similar in both fish and plankton fatty acids, thus suggesting the planktonic origin. During the period of abundant availability of plankton the changes in the fatty acids of the herring depot fat are related to the changes in the plankton lipid composition.