Ichthyofaunal diversity in tributaries of river Kosi, North Bihar

Abstract

Ichthyofaunal diversity of five tributaries, viz., Mithai dhar, Bhirkhi dhar, Gomati dhar, Budhma dhar and river Sursar of river Kosi, a largest tributary of river Ganga was recorded from January, 2019 to December, 2019. During the study period, total 45 species under 33 genera, 18 families and 8 orders were recorded from tributaries. The order Cypriniformes was the dominant group comprising 42.2% followed by Siluriformes 24.4%, Perciformes 15.6%, Osteoglossiformes 4.4% and Symbranchiformes 4.4%, Clupeiformes 2.2% and Tetradontiformes 2.2%. Cyprinidae family represented maximum number of fish species (15 species) followed by the family Bagridae (4 species). The study revealed that tributary has a rich ichthyofaunal diversity which was exploited for human consumption. Fishes like, Labeo rohita, Mystus vittatus, Mystus tengra, Wallago attu, Xenentodon cancila, Mastacembelus armatus, Channa punctatus and Channa marulius were the common species. Sorensen’s similarity index ranged from 43.9 to 65.0% shows more number of common species in all tributaries. The study revealed that as per IUCN criteria, 2 species were Vulnerable, 7 species Near Threatened, 33 species Least Concern, 1 species Data Deficient and 2 species Not Evaluated. While, according to CAMP status, 6 species were Endangered, 11 species Vulnerable, 16 species Lower Risk near threatened, 3 species Lower Risk least concern and rest 9 species Not Evaluated.