Influence of age on the reproductive biology of female Schizopyge niger (Heckel, 1838) inhabiting Dal lake, Kashmir

Reproductive biology of Schizopyge niger

Abstract

Schizopyge niger, a prized indigenous cyprinid fish of Kashmir valley, contributes significantly to the fish catch from the valley. They are highly valued fish with high demand locally and are preferred over most other native fish species. The study was aimed at investigating the effect of age on gonadotropins (GtHs), gonadosomatic index (GSI) and hepatosomatic index (HSI) of female Schizopyge niger. A total of 106 samples at random were collected from Dal Lake for this study during spawning season. Age of fish ranged from 2+ years to 6+ years with an average length from 119.39 to 292.17 mm. A significant correlation (p<0.05) was observed between total length and age of S. niger (R2=0.9959). The mean gonadotropin I (GtH I) and gonadotropin II (GtH II) values obtained during spawning season were 0.08±0.01 mIU/ml and 0.17±0.02 mIU/ml respectively. GtHs showed a strong relation with age with the maximum values obtained in age 6+ years. The gonadosomatic index (GSI) values ranged from 8.29% to 30.27% and had no correlation with age (p> 0.05). Hepatosomatic index (HSI) ranged from 0.47% to 2.63% and increased with age of fish. A positive correlation was observed between HSI and age (R2= 0.7004; p> 0.05). This study will provide baseline information for fisheries biologists about age related variations in the reproductive parameters of this species.