RELATIONS OF PHYSICAL HABITAT TO FISH ASSEMBLAGES IN STREAMS OF WESTERN GHATS, INDIA

The present study, the influence of habitat structure on fish assemblages were assessed in fifteen selected streams of Western Ghats, India. Each stream 100m reach was quantified for depth, flow, velocity, fish cover, percentage of pool and riffle and fish density. Highest mean velocity (0.4 m/sec.) was recorded in Thalanai stream and deeper habitats were found in Kallar stream. High species diversity was found in Achankoil stream (Hʹ=1.15) and low species diversity was recorded in Hanumannadhi stream (Hʹ = 0.71). The physical habitat structure (depth, current and substrate) and cover complex were evaluated by using Evenness index (Hʹ/Hʹmax). High diverse of physical habitat complex were encountered in Gugalthurai stream (E=2.8) and high value of cover complex was encountered in Sirkuli stream. Regression analysis showed that there was a significant correlation between habitat variables and fish abundance in all the sites and the cover complex values is not significantly correlated with abundance.