The life-cycle and productivity ofdiastylis rathkei(cumacea: crustacea) at three nearshore localities in the Hanö Bight, Southern Baltic

Abstract

Abstract The life cycle of Diastylis rathkei Kroyer at three depths in a nearshore area in the Hano Bight is described. Abundance varied over the 8 years of the study with very low values in the beginning and end of that period. A biannual life cycle dominated, with breeding in winter from October to April. Main recruitment occurred in February–March. Mature males were found only till the end of December each year. Both the number of eggs and the number of larvae were positively correlated with female length. Growth mainly occurred in late spring and summer. Annual P:B-ratios ranged from 0.84 to 3.73. The great variation was probably due to the influence of immigration to and emigration from the population in some years. The mean value of P:B at 17 m depth during three years without large population movements was 2.03.