The seasonal fluctuation of the mussel larvae in the northern Adriatic Sea

Abstract

The study of mussel larvae in the northern Adriatic Sea was undertaken in order to establish the seasonal fluctuations of the larvae in the plankton. The plankton samples were collected at four stations (Limski kanal, Banjole Island, Vela Draga and Pomer Bay) from 1965 to 1972. The observations showed that there are similar patterns of the presence of mussel larvae in the plankton in the northern Adriatic Sea. In well closed localities (Limski kanal and Vela Draga Bay) with shellfish culture parks the number of mussel larvae was larger than at an open sea station (Banjole Island). In Pomer Bay, in spite of the mussel cultivation, the number of mussel larvae was low and their settlement was slight, probably due to an unfavourable environment for their reproduction or the development of larvae. The seasonal fluctuations of mussel larvae in the northern Adriatic Sea are similar to those observed in some regions of the Mediterranean sea by several authors. We can conclude that in the Mediterranean Sea the mussel larvae are present in the plankton almost throughout the year.