Reproductive Biology of the Threatened Menoda Catfish, Hemibagrus menoda (Hamilton, 1822) in the Kangsha River, Bangladesh

Background and Objective: Knowledge of reproductive biology of a fish species is particularly important for conservation and plays significant role in determining its sustainable management and suitability for culture. Aspects of reproductive biology of Hemibagrus menoda from Kangsha River Netrakona district, Bangladesh were studied to evaluate the on-set and period of spawning season and its reproductive potential, which were hitherto not reported. Materials and Methods: A total of 479 females and 400 males were collected using Gill nets and Seine nets from March, 2015 to February, 2016. Gonadosomatic index (GSI), fecundity and histology of the gonads were investigated. Regression analysis was used to estimate the relationships between fecundity and standard length (SL), fecundity and body weight (BW) and fecundity and ovary weight (OW). Results: The monthly mean GSI of female H. menoda started to increase from May to June and reached the peak (12.50±4.97) in July, indicating the peak spawning season of the fish. Mean fecundity estimates based on mature females was 77273.77±276.82 for fishes with mean length of 31.85±2.39 cm and ranged from 22954.99; 25.00 (cm) in May to 222171.8; 40.20 (cm) in July. Fecundity correlated positively with SL (Log F = 0.0135+4.399 log SL; r2 = 0.774), BW (F = 198.7 BW-47602; r2 = 0.805) and OW (F = 1066 OW+6124; r2 = 0.832). Based on histological data, yolk vesicle, premature and mature stages of oocytes were abundant in May, June and July, which further confirms the distinct spawning season of H. menoda from May to July. Conclusion: Hemibagrus menoda spawns once a year and the spawning season extends from May to July with a peak in July. This reproductive pattern helps in development of culture program and conservation of the species.