Studies on the seasonal biochemistry of the Northern krillMeganyctiphanes norvegica in the Kattegat

Abstract

A well defined pelagic population of the Northern krill,Meganyctiphanes norvegica was sampled annually at a specific location in the Skandinavian Kattegat, and the major biochemical components were measured. Protein and lipid were the main constituents and underwent the most pronounced seasonal changes, clearly correlated to the prevailing supply of food organisms. The amount of lipid increased to a maximum of 48% of the dry weight towards winter, out of phase with gonad maturation, and therefore interpretable as deposition of overwintering reserves. Utilisation of stored reserves proceeds over winter, with loss of lipid, and decrease in weight but not in length. Comparison with literature data showed similarities with other krill populations from different geographical locations. The biochemical components ofEuphausia superba, the key organism of the marine Antarctic ecosystem, resembled those ofM. norvegica. Special polar adaptations are not obviously expressed in the proximate biochemical composition.