The Biochemical Composition ofEuphausia Superba

Abstract

Proximate analyses of deep-frozen samples ofEuphausia superbaDana obtained in December and January showed that protein was the major constituent, averaging just over 50% of the dry body weight. Lipid was much more variable; extreme limits of variation were from 6 to 33% dry weight, though the lipid content during January was distinctly higher than in December (means 27 and 13% dry weight respectively). This increase probably reflects a more intensive grazing by krill during the Antarctic summer. Increased lipid appears to be associated with some reduction in water content and in ash. Carbohydrate is low, the mean value for December being just under 5% dry body weight, but the content is slightly higher than that found for most zooplankton and may reflect the herbivorous habit ofE. superba.The proximate biochemical composition of krill is similar to that of the boreal euphausiid,Meganyctiphanes norvegica.