Dinâmica ovocitária associada as estratégias reprodutivas da Mugil curema (Mugilidae, Teleostei) na costa maranhense como medidas de gestão pesqueira

Abstract

The present study aimed to evaluate the oocyte dynamics and fecundity of the fish species Mugil curema as a tool to support conservation measures and sustainable use along the coast of Maranhão, Brazil. The study area comprised the coastal zone of Carimã and Curupu Islands, municipality of Raposa. Specimens were obtained through commercial fishing over a one-year period (May 2023 to April 2024). A total of 169 individuals were analyzed and transported to the Laboratory of Fishery Biology (BioPesq) at the State University of Maranhão for processing of biological material. In the laboratory, total length (TL), fork length (FL), standard length (SL), total body weight (TW), eviscerated weight (EW) (±0.01 g), and gonad weight (GW, ±0.01 g) were recorded. Subsequently, macroscopic identification of gonadal maturation stage and sex determination were carried out, followed by microscopic classification through histological analyses. The sex ratio was 1F:0.6M. The length at first maturity (L50) was estimated at 16.83 cm for females and 18.51 cm for males. Five gonadal maturation stages were identified: A – immature; B – developing; C – mature; D – spent; and E – resting. The classification of oogenesis stages in M. curema ovaries included oogonia, CA – cortical alveoli, Vtg1, Vtg2, and Vtg3 – primary, secondary, and tertiary vitellogenesis, respectively; hydration; POF – post-ovulatory follicle; and atresia. Absolute fecundity was estimated at 48,825 oocytes, with relative fecundity reaching approximately 102 (±4,882,500). In July, a peak of nearly 20% frequency was observed for oocytes with modal diameters ranging from 144 to 176 μm. The study of oocyte dynamics in M. curema revealed reproductive patterns influenced by environmental factors, which are essential for management and conservation strategies along the Maranhão coast.The study of oocyte dynamics in M. curema revealed reproductive patterns influenced by the environment, which are crucial for management and conservation strategies along the coast of Maranhão.