Fatty Acid Profiles as Natural Marks for Stock Identification

Publisher Summary Different species of fish have characteristic fatty acid profiles, but the variability in the composition of the tissue fatty acids of fish is very large. Different tissues have different fatty acid profiles. Within each type of tissue the fatty acids are bound in a number of different lipid classes, phospholipids, triacylglycerides, wax esters, cholesterol esters, and so on, all with different profiles. On top of these variations, the composition of tissue fatty acids may be influenced by factors such as age, maturity, condition, and reproductive cycle of the fish. External factors, such as water temperature and salinity, and probably also pressure, have been shown to have an effect on fatty acid composition. Numerous investigations have shown that the diet of fish has an impact on the fatty acid profile in fish tissues. With so many causes for variation of the relative amounts of 20 plus variables, that is, fatty acids, systematic investigations in this field were not possible until statistical, multivariate treatment of the analytical data (chemometry) was introduced by the author and researchers emerging from this group in the first half of the 1980s. With principal component analysis, one of the most used multivariate methods, it is possible to distinguish among the different internal and external causes of variation. The method also allows ranking of fatty acids according to their importance for the different variations.