As a part of investigation to explore useful constituents of plankton, we have taken up carotenoid pigments of the Antarctic krill Euphausia superba and analyzed their composition, The content of carotenoids in the frozen krill was determined to be 3-4mg/100g. The carotenoids comprised astaxanthin diester (I), astaxanthin monoester (II), astaxanthin (III), and unidentified ones (IV) in 40-50%, 30-40%, 15-25%, and 5-15%, respectively. In the case of the krill meal, the conten was 15-20mg/100g and the composition of I, II, and IV was 65-75%, 15-25%, and 5-15%, respctively, lacking III. Two kinds of unique colored carotenoids of dense crimson and of violet occupied the major part of IV. Both were supposed t be esters of retro carotenoids.
