The effect of salinity on spotting features of Salmo trutta abanticus, S. trutta fario and S. trutta labrax of cultured brown trout.

摘要

The aim of this study is to determine the effect of salinity on spotting features of Salmo trutta abanticus, S. trutta fario and S. trutta labrax of cultured brown trout. Salmo trutta abanticus, Salmo trutta fario and S.t.labrax were captured monthly from small streams and then to the laboratory then the fish were equally allotted to 3 groups with three replicates for each treatment and fed for 154 days. Each set consisting of one tank with running water from the Black Sea and one with running fresh water from nearby River Camburnu. Salinity was held at +or-0.5 ppt of the set-point by adjusting the make-up rate of freshwater and seawater. The results obtained in the present study indicated that salinity is an important factor and affected to spot in three ecotypes. It was observed that black spots and red spots in three ecotypes appeared prominently and trout had a brownish appearance when three ecotypes were transferred from sea water to fresh water. It was also determined that fish have been gained more weight in sea water than fresh water. It is suggested that the result be used to investigate to see if they could regain to the red spots provided that they are keep in fresh water for a longer period of time.