First sexual maturity and type of spawning of the fish Conodon nobilis (Linnaeus, 1758) from the Amazon coast - Brazil.

The study of reproductive biology is an important tool in identifying protective measures to preserve fish stocks, providing essential data for a reliable management system that ensures a balance between the environment and the economy. This study aims to analyze the first sexual maturity and type of spawning of the fish Conodon nobilis (Linnaeus, 1758) on the Amazon coast, specifically in the Gulf Maranhense region. 360 specimens were obtained from commercial fishing activity in the community of Raposa-MA during the period from January to December 2021. Biometric data were recorded, and the gonadal maturation stages were determined through macro (maturation scale) and microscopic (histology) analyzes. Sex ratio, mean length of first sexual maturation and type of spawning were determined. Negative allometric growth was recorded for both sexes, indicating a greater increase in length than in weight, and the length varied from 11 to 31.8 cm and the sex ratio was 1 male:1.5 female. Individuals in all stages of maturation were observed throughout the year, with a predominance of individuals in spawning capacity and reproductive peaks in January, April and May, indicating that the species presents multiple spawning. The length at first sexual maturity (L50) for females was 18.41 cm and for males was 18.91 cm. Knowledge of the mean size at sexual maturity can help define appropriate regulations for fishing, ensuring that individuals have the opportunity to reproduce at least once before being captured.