Reproductive timing and spawning dynamics of European barracuda Sphyraena sphyraena in eastern Mediterranean Sea.

Abstract

This research investigated the reproductive timing and spawning dynamics of the European barracuda Sphyraena sphyraena in the Thermaikos Gulf, northern Aegean Sea, where the species is predominantly harvested using gillnets. The study was conducted over 2 years, from May to October, coinciding with the period when the local gillnet fishery targets surmullet Mullus surmuletus. The timing of reproduction was examined by the gonado-somatic index, the macroscopic assessment of the ovarian stage, and the microscopic examination of the ovarian developmental stage. All three indices demonstrated that spawning-capable females were caught in May and June and that spawning ceases by late July to August. Regarding spawning dynamics, the European barracuda is a multiple spawner; the oocyte size frequency distributions of all spawning-capable and actively spawning females were continuous, and postovulatory follicle cohorts from different daily spawning events co-occurred in the ovaries of many of those females. Relative batch fecundity was rounded off to 197 ± 108 oocytes per gram and relative total fecundity at 1263 ± 513 oocytes per gram. The somatic condition increased in postspawning individuals, suggesting a capital breeding reproductive strategy.