A study was conducted to determine the ichthyofaunal diversity in Bankura district of West Bengal. The area is traversed by major and minor rivers, feeder channels, numerous ponds, bills, reservoirs which have made this drought-trodden district as the highest producer of aquatic products within the state. Field survey was conducted in randomly selected local markets covering twenty-two blocks of Bankura. Fish sampling was carried out using various conventional fishing gears. The entire region harbours a wide variety of aquatic fishes. A total number of 92 indigenous fish species belonging to 30 families were identified during this study. The Cyprinidae family dominated the population with its 36 varieties followed by Channidae, Siluridae and Bagridae. Sonamukhi block situated in Shali basin; Sarenga and Raipur of Kangsabati basin; Dwarkeshwar and seven bundhs- enriched Bishnupur were the major habitats of small indigenous fishes. This paper also denotes presence of 12 globally endemic freshwater fish species viz. Hypophthalmichthys molitrix, Cyprinus carpio, Labeo nandina, Tor khudree, Chitala chitala, Bagarius bagarius, Wallago attu, Ompok pabda, Ailia coila, Anguilla bengalensis, Parambassis lala, Oreochromis mossambicus. The substitution of native Clarias batrachus with invasive African catfish C. gariepinus was observed in various local markets. Some traders even promote illicit farming of this banned species for their own profit. As a consequence, the indigenous, nutritionally-enriched C. batrachus is becoming more endangered.
Evolutionary time best explains the latitudinal diversity gradient of living freshwater fish diversity
