The present work focused on exploring reproductive biology of fish from different major rivers of India and their tributaries by comparing ovarian protein, fecundity, oocyte weight, oocyte diameter and condition factor during the spawning period. Significant correlation was found between reproductive parameters of fish in the major rivers and their tributaries. Among the parameters studied fecundity showed the highest correlation with ovarian protein level and oocyte weight in the major rivers, whereas in tributaries it was highly correlated with ovarian protein. The results from a wild population showed that the fecundity and ovarian protein level were significantly higher in the Narmada River, and the lowest in river Ganga (U.P.). Among the tributaries, maximum ovarian fecundity was observed in fish with the highest protein concentration from River Hooghly. The condition factor (K) in femaleOmpok bimaculatuswere reported to be significantly high in the major River Cauveri and Sharda tributary. The oocyte weight was significantly higher in the major River Krishna and the lowest in fish from River Godavari. In fish samples collected from tributaries, those Sone River showed the highest oocyte diameter and fish from Betwa River showed the lowest oocyte diameter. It can be concluded that the aquatic atmosphere in the local area plays an important role in species specification and can affect their reproductive performance as well as their survival.

Keywords: Fecundity, Oocyte diameter and weight, Condition factor, Ovarian protein concentration,Ompok bimaculatus