Seasonal Fluctuations in the Sex Ratio of the Striped Snakehead, Channa striata (Bloch 1793), from Nagapur Dam, Maharashtra, India

The striped snakehead, Channa striata, is a commercially and ecologically significant freshwater fish in South and Southeast Asia. Sustainable management of its populations requires a thorough understanding of basic demographic parameters, such as the sex ratio. This study investigated the annual and seasonal sex ratio of C. striata in the Nagapur Dam, Beed district, Maharashtra, a semi-arid region for which such data is lacking. A total of 178 specimens were collected monthly from local fishermen from January to December 2024. Sex was determined through macroscopic and, when necessary, microscopic gonad examination. The overall annual sex ratio was 1.14:1 (male:female), which did not deviate significantly from the expected 1:1 ratio (χ² = 0.719, p > 0.05). However, significant seasonal variations were observed. The sex ratio was balanced at 1:1 during summer but became significantly skewed towards females (1:1.78) during the monsoon (χ² = 5.062, p < 0.05). A male-biased ratio (1.35:1) was observed in the post-monsoon season, though it was not statistically significant. The pronounced female bias during the monsoon is likely due to the increased vulnerability of gravid females to fishing gears during their spawning migration. These findings suggest that the current unregulated fishing during the breeding season could negatively impact recruitment. We recommend implementing a seasonal fishing closure during peak monsoon months to protect spawning females and ensure the long-term sustainability of this valuable fishery.