Reproductive biology of the European pilchard (Sardina pilchardus (Walbaum, 1792)) in the Marmara Sea and the Aegean Sea, Türkiye

This study examines the reproductive biology of the European pilchard using samples collected from commercial fisheries in the northern Aegean Sea and the southwest Marmara Sea in 2024. Specimens were collected monthly using purse seines between September 1st and April 15th and gillnets between April 15th and August 1st. Mean total length and body weight of individuals sampled by both fishing gears were generally higher in the Aegean Sea than in the Marmara Sea. The female-to-male ratio was estimated as 1.0:0.77 in the Aegean Sea and 1.0:1.12 in the Marmara Sea. Length–weight relationship analyses indicated predominantly negative allometric growth for both sexes and for the overall population in both regions, except females from the Aegean Sea. The length at first maturity was higher in females than in males and was greater in the Aegean Sea compared to the Marmara Sea. Based on gonadosomatic index, condition factor, and maturity stages, the spawning period extended from November to April, with peak spawning in February. These findings provide updated regional information on key reproductive parameters of European pilchard and contribute valuable data for stock assessment and the sustainable exploitation of this ecologically and economically important species in Turkish seas.