STUDIES ON THE LIMNOLOGICAL VARIATIONS AND ITS EFFECT ON FISH PRODUCTION OF HANNA LAKE AND ZHOB RIVER,BALUCHISTAN, PAKISTAN

Abstract

The limnological studies of Hanna Lake and Zhob River were carried out from January – December 2011. The study revealed that there is no significant (p ≥0.05) difference was recorded in the values of temperature, transparency, pH, DO and TDS from both sampling sites, but significantly (p ≥0.05) was noticed in the values of conductivity and salinity. The conductivity and salinity values were found to be higher (268-351mg/L and 0.8-32 ppt respectively from Zhob River, Balochistan. The length –weight relationship values indicated that growth of C. auratus and Glypothorax sp.were found to be negative allometry and regression co-efficient (b = 1.70 and 1.50 respectively), indicated as poor growth of two fish species from Hanna Lake, Balochistan. The values of relative condition factor (Kn) was calculated for combined sexes for both the fish species (mean Kn = 0.98 and 0.96) in case of C. auratus and Glypothorax sp. As for as Zhob River is concerned, the length –weight relationship values indicated positive allometry and regression co-efficient (b= 2.27, 2.25, 2.65 and 2.67), indicated as ideal growth of all fish species from Zhob River, Balochistan The values of relative condition factor (Kn) was calculated for combined sexes for 04 fish species (mean Kn= 1.0, 1.01, 0.97 and 1.31) in case of C. auratus and S. progastus, Tor tor and Glypothorax sp. In the present study the seasonal Zooplankton distribution of Hanna Lake showed that the highest Zooplanktons were recorded during March- August 2011, while lowest were observed during November to December 2011. In case of Zhob River the highest Zooplankton were recorded during July- August 2011 and lowest during November – January. It was concluded that theCalanoida, Bosmina andDiapanosoma was recorded as dominant species of Zooplanktons observed from both the environments.