Effects of fish size and breeding tubercles on gonadosomatic index and some spermatological parameters in the Mahisefid Rutilus Frisii kuttum kamensky 1901

The tubercles of teleosts are induced by several sex hormones and fall off shortly after spawning. During this study which was carried out in Gorganrood for 3 months, the correlation between secondary sexual characters and fish size with gonadosomatic Index and spermatological parameters (spermatocrit, sperm volume, sperm concentration and duration of sperm motility) of Mahisefid Rutilus frissi kutum kamensky 1901 was investigated. 10 samples semen of Mahisefid was gathered with 5cc syringes and immediately were transferred to laboratory with ice flask and based on the number of their breeding tubercles divided to 3 categories: tubercles>100 (1 treatment), 80-100 (2 treatment), and tubercles <80 (3 treatment). With increase of head tubercles, total length (P<0.05), sperm volume (P<0.01) and gonad weight (P<0.05) was increased. But duration of sperm motility, spermatocrit, sperm density and gonadosomatic index were not influenced with the number of head tubercles (P>0.05). The results of Pearson test indicated that head tubercles with total length, total weight and gonad weight (P<0.01) and sperm volume (P<0.05) was correlated significantly. But no significant relationships (P>0.05) were found between gonadosomatic index with sperm parameters and fish size.