Spermatocrit and sperm density in snowtrout (Schizothorax richardsonii): Correlation and variation during the breeding season

The efficacy of spermatocrit (the ratio of packed sperm cell in semen after centrifugation) as an indicator of sperm density was tested in snowtrout (Schizothorax richardsonii). Semen samples were collected from 98 live ripe male brooders over two consecutive breeding seasons for the sperm density analysis. A significant, positive, linear relationship between spermatocrit and sperm density (measured with a haemocytometer) was established during regression analysis (r = 0.817, P < 0.001), thus supporting the use of spermatocrit as a rapid and reliable estimator of sperm concentration in this species. A decrease in sperm density and spermatocrit was noticed with the advancement of breeding season.