Reproductive aspects of Anabas testudineus collected from the Gajner Beel wetland in Bangladesh: implications for its conservation under changing eco-climatic conditions and suggestions for best aquaculture practice

The freshwater climbing perch, Anabas testudineus , is an economically and nutritionally valuable food fish. This study explores the various reproductive contents (size at sexual maturity, reproductive period and fecundity) of A. testudineus in the Gajner Beel concerning the eco-climatic variabilities and suggests sustainable management policies. A total of 709 individuals were randomly collected from January to December 2019 among 371 females that were sorted out for this study. Total length (TL) ranged from 7.50 to 16.40 cm. Based on the maximum length ( L max ), TL vs . gonadosomatic index (GSI), TL-standard length (SL) regression and logistic model, the size at sexual maturity ( L m ) was 10.00 cm, 10.40 cm, 11.00 cm and 11.50 cm, respectively. The spawning season was May to August and peaked in June–July. The Fulton’s condition ( K F ) was suggested as the best condition factor ( p < 0.0001), and relative weight ( W R ) showed no significant difference from 100 for females ( p = 0.143) . Fecundity was ranged from 9459 to 35,915. A significant relationship was observed between GSI and temperature ( p = 0.0016), dissolved oxygen (DO) ( p < 0.0001), pH ( p < 0.0001), alkalinity ( p < 0.001) and climatic parameters (air temperature, p < 0.001 and rainfall, p < 0.001). The data series of 48 years (1971–2019) revealed that the rise of average air temperature by 0.029 °C and the reduction of rainfall by 2.96 mm per year might shift the spawning season of A. testudineus 15–20 later. Therefore, this study will be helpful for the sustainable management and conservation of the wild stocks of A. testudineus in the Gajner Beel and adjoining ecosystems.