Reproductive biology of Lepidocephalichthys guntea: a key conservation approach considering environmental factors in Payra River, Bangladesh

The guntea loach, Lepidocephalichthys guntea , is categorically common freshwater fish in Southeast Asia. Current study is the first elucidation on the reproductive feature of L. guntea including population structure, sex ratio (SR), size at first maturity ( L m ), breeding period, and condition factor, emphasizing on the effect of environmental factors on reproduction of this fish in the Payra River (Southern Bangladesh) during July 2021 to June 2022. Using various conventional gears, 1128 individuals (534 males and 594 females) have been collected. Total length (TL), standard length (SL), and body weight (BW) of each fish were measured. Ovaries were cautiously dissected, removed, and precisely weighed. TL ranges from 4.6 to 9.7 cm (BW = 0.7–9.27 g) for male and 4.6–10.3 cm (BW = 0.8–10.75 g) for female. Both male (47.34%) and female (52.66%) populations were the leading group in 7.00–7.99 cm TL. Overall SR was not notably altered from anticipated value of 1:1 (male:female = 1:1.11). Nonetheless, monthly variations of SR specified females were considerably outnumbered males in each month excluding March–May. L m range was 6.4–7.0 cm, so larger than L m is recommended to exploit. Monthly changes in GSI indicated that the main spawning season was from March to June. The spawning season was substantially correlated with rainfall, nonetheless with temperature. Additionally, relative weight indicated that habitat was imbalanced with higher predators. A fishing ban is recommended during peak spawning to protect L. guntea in the Payra River and its surroundings based on current research.