Analysis of trophic gradient through environ-mental filter influencing fish assemblage structure of the river Teesta in Eastern Himalayas – JBES

sewell15Munmun Chakrabarty, Sumit Homechaudhuri

Aquatic Bioresource Research Laboratory, Department of Zoology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata-700019, India

Key words: Hill-stream, ichthyofauna, dietary composition, feeding guild, niche filter.

Abstract

Factors controlling biodiversity and co-existence of species need immediate attention to maintain biodiversity. Co-existence between interacting species is based on their ecological niches or functional roles and can be assessed by niche assembly theory and construction of trophic guild. In the present study, the diet composition of fishes have been analyzed both qualitatively and quantitatively to describe feeding patterns along environmental gradient towards linking biodiversity with functional diversity patterns to shape species assemblage. We evaluated the trophic guild structure of 92 fish species of the large, torrential river Teesta (within West Bengal) having its origin in eastern Himalayas. maxresdefaultStomach contents of 1515 fish specimens have been analyzed and fishes were ascertained 14 different trophic guilds. Canonical correspondence analysis was performed to study species associations with environmental parameters. Preliminary analysis showed a dietary shift of the respective fish assemblages from high to low altitude from specified feeders (aquatic insectivores) to omnivorous respectively. Aquatic insect larvae formed the most important prey in general, especially in high altitude zone followed by algae. The dietary preferences indicate that fish assemblage pattern seems to be guided by niche breadth and environment acting as the main filtering agent towards species sorting and survival. This study is an important step in structuring fish community of the River Teesta and to lay the foundation for subsequent future efforts on the conservation of aquatic communities and their feeding habitats.

jbes-vol4no4-p218-232Get the original articles in Source: Volume 4, Number 4, April 2014 – JBES

Journal Name: Journal of Biodiversity and Environmental Sciences (JBES)

Published By: International Network for Natural Sciences

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