A New Approach to the Assessment of Longevity in the Antarctic Krill Euphausia Superba

Abstract

Previous research to ascertain the life cycle and longevity of the Antarctic krill Euphausia superba by means of length-frequency distributions is reviewed; this traditional method has led to widely differing answers. In the light of new knowledge that the overwintering strategy of krill involves negative growth, such an approach is unrealistic. The assay of lipofuscin (a fluorescent pigment that accumulates in all cells of aerobically respiring organisms as a function of physiological time) may offer a solution to this problem. The lipofuscin content and morphometric parameters of a sample of gravid females were measured. On the basis of the lipofuscin assay, three year groups were defined. Discriminant functions were calculated showing that the year classes could be distinguished on morphological characters alone.