Abundances and Habitat Sensitivities of Some River Fishes in Thailand

Abstract

Freshwater fishes from a diverse array of 11 families, some dominated by marine species and others containing only a few species, were collected by electrofishing from 84 locations on small rivers in central Thailand and their abundances related to habitat characteristics. Abundances were largest for Channa gachua, Dermogenys pusillus and Mastacembelus armatus but for none of the 18 species were they large relative to the total numbers of fish captured. The importance of habitat characteristics to abundance was examined by multiple regression analysis for those species captured at more than 12% of the stations. Only a small number of habitat characteristics were significant for each species and no factor was common to all species. It is suggested some habitat characteristics are important through their influence on diet while for others the impact is on their physiology.