Biology of the suprabenthic mysid "Schistomysis assimilis" (Sars, 1877) on Creixell beach, Tarragona (northwestern Mediterranean)

The suprabenthic mysid Schistomysis assimilis (Sars, 1877) was sampled monthly during 19911992 in the surf zone of Creixell beach (Tarragona, Spain, northwestern Mediterranean) in order to describe its life history and estimate its secondary production. In the unstable coastal soft-bottom environment studied, this resident mysid is one of the suprabenthic community’s dominant species. Demographic analysis suggests that it is a trivoltine species with a potential longevity of less than one year. According to the size frequency method, its annual production