Population ecology of Cyprideis torosa (Jones, 1850) in a hypersaline environment of the Western Mediterranean (Santa Pola, Alacant) (Crustacea : Ostracoda)

The life cycle of the ostracod Cypideis torosa was studied in a hypersaline environment at Santa Pola, a coastal salt marsh of the Western Mediterrane an. Benthic samples were obtained monthly and several environmental factors were recorded simultaneously in situ. In Santa Pola, C, torosa is able to produce eggs all year round and, in contrast with previous studies, showed a bivoltine reproductive pattern. The first generation, starting from eggs produced in spring, attains adult size after a mean time of 154 days. The s econd generation, starting in autumn, developed more slowly, attaining adul thood after 196 days on average. The male:female sex ratio is below 1 in sp ring and autumn, when maximum reproduction took place, and it was not diffe rent from one after these periods. The mean shell size of adult individuals underwent significant changes throughout the year: late winter males and f emales are the longest. Those adult individuals that remained alive after t he spring reproductive period showed the lowest shell length values. We dis cuss how temperature and salinity may affect the development of juveniles a nd adult shell size.