Seasonal variation of Ichthyofaunal diversity and it’s relation with substratum in the River Changa, West Bengal, India

Abstract

Aim: A survey was conducted at four sampling sites of the River Changa to study the fish diversity in relation to river substratum. The aim of the study was to prepare a check list of ichthyofaunal diversity and their habitat preference guild in relation to sediment type. Methodology: Ichthyofauna was collected from four selected stations at monthly interval with the help of fishermen using gill net and cast net. For the analysis of the riverine substratum, sediment samples were collected from six square inches area at the sampling sites of the river by grab sampling method. The composition of stones, pebbles, sand and mud were evaluated from the sample. Results: A total of 64 fish species belonging to 6 families and 18 orders were recorded. Among which 33 were cold water fishes, 31 were warm water fishes, 28 were rheophilic and 24 were eurytopic fishes. Site 1 and 2 were dominated by rheophilic and cold water fishes and Site 4 was rich in eurytopic and warm water fishes. Cypriniformes was the most dominant order with 42 fish species. River sediment of Site 1, 2 and 3 were dominated by stones, pebbles and sand, while sediments collected from Site 4 was dominated by sand and mud. Cold water and rheophilic fishes were positively influenced by stones and pebbles. Eurytopic and warm water fishes were positively influenced by sand and mud. Interpretation: Cold water and rheophilic fishes were abundant at upstream of the river and eurytopic and warm water fishes were abundant at downstream of the river. Abundance and distribution of fish species depends on the river substratum. Key words: Ichthyofaunal diversity, Rheophilic, River Changa, River substratum