Reproductive cycle of Glycymeris nummaria (Mollusca: Bivalvia) from Mali Ston Bay, Adriatic Sea, Croatia

Abstract

The reproductive cycle of the dog cockle, Glycymeris nummaria (Glycymerididae), was studied using specimens collected monthly from Mali Ston Bay, southeastern Adriatic Sea over the period from January to December 2010. We analysed sex ratios, gonad developmental stages, and oocyte diameters using standard histological techniques. There were no differences in the overall sex ratio and no difference in shell length with respect to sex. Results of a size-frequency analysis of oocyte diameters agreed with a qualitative analysis of gonadal developmental stages, confirming the occurrence of one annual spawning peak from May to July. A significant correlation was identified between mean gonad indices of males and females and condition index. This study provides the first data on the reproductive characteristics of G. nummaria, providing necessary information for the future sustainable management of its potential fishery.

Keywords

• reproduction
• bivalvia
• glycymeris nummaria
• adriatic