Impact of enviornmental stress on certain fishes of River Periyar

Abstract

The present study has been taken up to highlight the deterioration of the water quality of Periyar river, especially the lower industrial belt area, and its stress impact on two selected fishes, Puntius sophore (Hamilton) and Horabagrus brachysoma (Gunther). Water quality studies in five selected sites of Periyar river were carried out during the premonsoon, monsoon and post-monsoon seasons for two years (2002-2004). The stress effect on the haematology of the two fishes exposed to different concentrations of the polluted water from Site-V for various durations were evaluated. Physico-chemical analysis of water of Periyar river revealed that the Site-V (Eloor industrial belt area) showed conspicuous significant variations in the different parameters analyzed. It was also noted that water quality found more deteriorated during pre-monsoon and postmonsoon compared to monsoon season. Conspicuous haematological changes were observed in the experimental fishes exposed to different concentrations of the polluted water from Site-V for various durations. The changes were found to be species specific. In all the parameters studied it was found that P. sophore is more vulnerable than H. brachysoma, which exhibited lower mortality rate. The studies revealed the acute toxicity of the polluted water in the Eloor region. H. brachysoma was found more resistant to the pollutants than P. sophore indicating the differential adaptive abilities of the fishes. The season wise effect of water pollution induced on the fishes illustrated the pollution stress scenario of the river. The information generated in the present investigation, with the two fishes as indicators of pollution stress, reflects the possible impact of pollution on the multitude of life forms in the river and the ecosystem.