Study of Using Monogenea Parasites on Free – Living Fishes in the Lake of 16 Tishreen Dam as Bio Indicators of Environment Pollution

The aim of the study was to develop a data base about the water quality in the Lake of 16 Tishreen Dam through, study was performed to determine of non biotic factors values of water in Lake and infecting FreeLiving fishes with monogenea parasites, and finding a relationship between parasites distribution and environmental conditions changing. 144 Free – living fishes were examined for detecting the infection with parasitic monogenea, and determine their distribution rate. Fishes were collected randomly once a month, during the period from 12/2012 until 11/2013. Collected fishes samples were belonged to the following species: Cyprinus carpio L., Varicorhinus damascinus, Garra rufa, Tilapia zillii, and Liza abu. T. zillii was the most prevalent one. Fishes were infected with monogeneaparasites, 6 species were isolated and classified. they belonged to four Genera, they were: D. lenkorani, D.extensus belong to the Genus (Dactylogyrus SP.), two species of (Gyrodactylus sp.) are:G. Medius and G. Mugilis, and one species of Cichlidogyrus sp. C. sclerosus, and one species of Microcotyle Sp. Isolated parasitic species were recorded for the first time on the free living freshwater fishes in the lake of 16 Tishreen dam, while by four species of them were recorded for the first time in Syria :( D. lenkorani, G. mugilis, C. sclerosus, Microcotyle.sp ) in this study. Monogenic Parasites showed high specificity to the host, and infected organ. General rate of infection with monogenic parasites was 27.1%. Varicorhinus damascinus was more infected than Tilapia Zillii in rate 35.71%, 28.72%. respectively the highest infection rate with monogenic on free living fishes was recorded in summer (High temperature and low concentration of dissolved oxygen, and slightly higher value of BOD). Study showed that the lake of 16 Tishreen Dam was relatively clean. Cichlidogyrus sclerosus was the most important monogenic parasites used as bio indicator of environmental pollution in the lake.