Ecological investigation on Dez dam lake

station in Dez river (after dam ). Station five in enterance of the river to lake showed riverine or lake condition according to water supply. In spite of significant difference between monthly sampling no significance were observed in depth and stations and the physico chemical results showed that all of the studied factors were in optimal range for fish culture and qrowth . The most dominant phytoplanktons were observed in Mar. and Aug. respectively. The most dominant zooplankton were in Feb .Cyclotella was the most abandance genus from sixtheen identified phytoplanktons genera. Dinophycea and Bacillariophycea were the most abundant classes from five main classes of phytoplanktons. Dinophycea showed same abundance in different depth but Bacillariophycea was dominant in surface. From nine genera of zooplankton groups include Protozoa , Rotifera , Cladocera and Copepoda , Brachinus was the most abundant genus. Benthic fauna include Oligochaeta , Corbicula and Chironomids larvae were more abundant in stations one & two in late spring and summer. Station three and four due to higher depth and station five due to comprise special condition and unstable bottom , showed low diversity and abundance. In this study 12 fish species , belong to 3 family , were identified and Cyprinid fishes with nine species were the most dominant family. Capoeta trutta , Barbus grypus and Barbus esocinus were the most species respectively . The most abundant fishes was observed in summer. Indices: diversity, richness , evenness and dominance 1.11 , 1.05 , 0.45 and 0.46 were determined respectively . Most of fishes were omnivor and also planktivor , carnivor fishes were observed. Spawning of the most species is occurred the late winter and spring and some species was spawning in different seasonal time. According to the result , Dez lake can be clssified as oligotroph mesotroph lake .

Iranian Fisheries Science Research Institute

Published