On the occurrence and biology of some Antarctic Mysidacea (Crustacea)

摘要

10 species of Mysidacea were sampled during thePolarsternandWalther HerwigSIBEX cruises to the Antarctic Peninsula region from 1983 to 1986. The commonest wereAntarctomysis maxima, A. ohliniandMysidetes posthon. For these species the size and maturity stage composition as well as the length-weight relationships are given. The species considered are growing slowly and attain a long life span,M. posthonreached age class 3+,A. ohliniat least lived as long as 5 years, whileA. maximawas found to be of age 5+ in the Peninsula area and probably 6+ in the Weddell Sea. The generation time ofAntarctomysisspecies was 4 years and 3 years inMysidetes posthon. Fecundity was low, mean number of offspring was about 13 forM. posthonand 21 forA. maxima. Rematuration was observed for the speciesA. maxima, indicating several spawning events during its life span. Biomass production is low forA. maxima, shown by a P/B-index of 0.98. Mortality of this species was estimated to be Z=1.1, which indicates that 33 of the specimens of an age group survive until the next year. The distribution and spatial separation of the two Antarctomysis species is discussed.