LENGTH AND AGE AT MATURITY OF ANTARCTIC KRILL

Data from several summer research cruises in the Antarctic Peninsula r egion were analysed to calculate length (L(50)) and age at maturity fo r the Antarctic krill, Euphausia superba. Length at maturity L(50) is defined as the length at which 50% of the krill stock attains sexual m aturity. L(50) values of 34.65-35.91 mm for female krill are the best estimates for the peak spawning season. Males attain sexual maturity l ater at L(50) values of 43.35-43.71 mm, Length at maturity and length at first spawning are identical for krill. Comparisons with mean lengt h-at-age data show that females mature in the third growth season (age class 2+), while males reach maturity in the fourth year (age class 3 +). Both sexes show 'knife-edge maturity'.