Fish diversity in relation to physico-chemical characteristics of Bhadra reservoir of Karnataka, India

Abstract

The fish community of the Bhadra reservoir in relat ion to physic-chemical parameters was studied by monthly samples taken from June-2004 to May-2005. This water body is situated at 13 o 42 | N latitude and 75 o 38 | E longitude located near Lakkavalli town of Chikma glore district, Karnataka and the confluence of the Bhadra River. T he water of the reservoir is used for producing electricity, fishery and tourism activiti es. Fish collections were done with gillnets of standardized dimensions with several mesh sizes. 33 fish fauna identified during the study belongs to Cyprinidae 18 species, Channidae 2 speci es, Bagridae and Siluridae with 3 species and a species each of Mastacembelidae, Ambassidae, Cichlidae, Claridae, Notopteridae, Cobitidae and Heteropneustidae. Besides identificat ion, relative occurrence and economic importance of fishes are discussed. All fishes are useful as food fishes except Ambassis, Puntius and Gambusia, which are useful as ornamental and la rvicidal fishes. The species diversity is peak in post monsoon, coinciding with favorable con ditions such as sufficient water and ample food resources. The diversity was low in premonsoon probably due to the shrinkage of the water spread of the reservoir. The high value of dissolve d oxygen coupled with low biochemical oxygen demand and other nutrient levels indicate that the water body is moderately oligotrophic in nature. The factors responsible for declining popul ation of fish species is discussed in detail. To save this diversity and to develop a sustainable fi shery practices and proper documentation leading to diversity information system is an urgen t need.