Reproductive performance of Asian stinging catfish Heteropneustes fossilis (Bloch 1794) in the Ganges River (NW Bangladesh) in relation to environmental factors

Reproduction plays an important role in fish population efficiency and its resiliency to fishing and environment changes. The present study described the comprehensive information on reproductive feature of stinging catfish, Heteropneustes fossilis (Bloch 1794), including size at sexual maturity, spawning season, and fecundity using 622 female individuals sampling by the use of gill net, cast net, and square lift net from January to December 2019 in the Ganges River. We calculated the influences of various environmental parameters which include temperature, dissolved oxygen, pH, and rainfall on the reproductive feature of H. fossilis in the Ganges River. For every specimen, total length (TL), standard length (SL), and body weight (BW) were estimated by measuring board and electronic weighing scale. With ventral dissection of fishes, female gonads were cautiously removed and measured to 0.01 g precision. The gonadosomatic index (GSI), modified gonadosomatic index (MGSI), and Dobriyal index (DI) were used to assess the size at sexual maturity (Lₘ) and spawning season. According to the results of these indices, Lₘ was obtained 15.5 cm in TL. Also, TL₅₀ was determined through logistic function as 15.5 cm in TL. Moreover, the highest GSI, MGSI, and DI values indicated the spawning season as of March–August, with peak in May–June. Total fecundity (FT) varied from 2059 to 59,984 with a mean of 25,028 ± 15,048. Temperature and rainfall was statistically correlated with GSI. In addition, long climatic data series analysis denoted that yearly mean atmospheric temperature is rising in 0.028 °C/year and yearly mean rainfall is declining in 2.98 mm/year which may suggest a potential shift of the spawning period of the species in the future if this trend persists. The results of our study might be more useful in imposing particular management and conservation for H. fossilis in the Ganges River and the surroundings.