The study of Scott fish’s (Scatophagus argus) adaptation in freshwater environment

In this study the ability of adaptation and growth rate of salt water fish (Scatophagus argus) in freshwater environment were investigated. This fish naturally lives in salinity between 16-20 ppt. Four treatments of salinity (0-10-20 and 30 ppt) in 3 replicates and per replicate including 6 fish were selected. After the adaptation period, from each treatment, one fish randomly selected and the methods of tissue sections prepared and stained (hematoxylin - eosin) was performed on organs of kidney and gill. The results of the microscopic changes in chloride cells were examined. Based on the results of specific growth factors increases, obesity rates and the percentage of survival of juveniles in different treatments did not show significant difference (p>0/05). The highest specific growth rate and the lowest rate of obesity were found in the salinity of 20 ppt and 30 ppt, respectively. The highest percentage survival and the survival of juveniles was observed at salinity of 10 ppt. Survival rate of fish in fresh water was same with the salinity of 20 ppt that is suitable salinity for Scott Fish in the environment. During the examination period, the photograph was taken from the tissues of kidney and gill by light microscope. After counting the gill chloride cells and of kidney it was clear that with the reduction of salinity, chloride cells of gills decrease and of kidney were increased )P<0/05).