Fecundity, Length at First Sexual Maturity and Gonadal Development of Lepidorhombus boscii in the Eastern Adriatic Sea

SIMPLE SUMMARY: Lepidorhombus boscii is a flatfish of high commercial value. However, the existing knowledge about the biology and ecology of this species is scarce. The aim of this study is to describe the reproductive cycle of L. boscii in the eastern Adriatic Sea. The sex ratio of L. boscii was 1:0.89 (female:male), and the size at first sexual maturity was 19.2 cm for females and 20.3 cm for males. Previtellogenic and vitellogenic oocytes are present in the ovaries throughout the year. L. boscii has a prolonged spawning season in the Adriatic Sea with the main spawning season between November and March. ABSTRACT: This study presents data on the seasonal changes in population structure, maturation, fecundity and reproduction of the Lepidorhombus boscii from the central-eastern Adriatic Sea. This species is a commercially valuable fish in the Adriatic Sea; still, knowledge about its reproductive biology is very scarce. The analyses are based on the data collected between July 2020 and June 2021 by bottom trawls. In total, 963 individuals were collected out of which 508 were females (47.24%) and 455 were males (52.75%). Throughout the year, oocytes in the previtellogenic and vitellogenic stages were present in the ovaries, and the development of the ovaries followed the values of the gonadosomatic index. L. boscii has asynchronous ovarian development and a prolonged spawning season in the Adriatic Sea with the main spawning season between November and March. The oocyte diameter ranged from 34.01 to 562.72 μm (178.49 ± 129.83 μm). This study presents the first information on the reproductive cycle of L. boscii in the eastern Adriatic Sea and contributes to the understanding of the biology of this species necessary for its sustainable management.