Sexual Maturation of Fan Mussel Pinna nobilis (Linnaeus, 1758) (Mollusca: Bivalvia) in Experimental Cages in the Mali Ston Bay (South Adriatic Sea)

Abstract

The research included 120 specimens of Pinna nobilis cultivated at a commercial park for oyster (Ostrea edulis) and black mussel (Mytilus galloprovincialis) cultivation. Research was carried out from 2012 to 2016, prior to the start of the mass extinction of fan mussel in the Mediterranean During the study period, the average sea temperature at a depth of 3 m was 14.87 ± 4.22 °C, ranging from 7.83 to 24.90 °C. The age of the specimens at the beginning of sexual maturity was approximately three years. The average length of the specimens throughout the study was 293.01 ± 16.58 mm. Gonad status was monitored monthly by sampling. The gender ratio in the study was 46 females (38.4%), 50 males (41.6%), and 24 undetermined individuals (20%). In our study, the results showed that males mature slightly earlier than females. The main spawning season occurred during the warmer part of the year when seawater exceeded 18 °C, starting in May and lasting until November. During the study, the GSI varied as expected and peaked in June (12.1), increasing from May to September.