Lipids and Fatty Acids of Two Species of North Atlantic Krill (Meganyctiphanes norvegica and Thysanoëssa inermis) and Their Role in the Aquatic Food Web

Abstract

The fatty acid compositions of phospholipids and triglycerides from two lots of Meganyctiphanes norvegica (M. Sars), and of total lipids of two additional lots of different origin, showed characteristics commonly found in lipids of carnivorous higher animals such as herring. The fatty acids in both phospholipids and triglycerides of one sample of Thysanoëssa inermis (Krøyer), although qualitatively similar to those of the M. norvegica lipids, showed a closer quantitative relationship to phytoplankter fatty acids and suggested that this species is herbivorous. These observations are discussed in terms of biological data on the feeding habits of the animals, and their basic biochemical processes as related to overwintering or other times of food scarcity. The crustacean samples, obtained from the stomachs of fin whales captured off Nova Scotia, had 1.2–2.4% total lipid, with nonsaponifiable materials accounting for 3–5% of the lipids in M. norvegica and 10% in T. inermis. The potential utilization of these species in artificial rearing of trout or salmon is discussed.