Author(s): Yashpal Singh, Saurabh Dewan and JP Bhatt

Abstract: Accurate knowledge regarding gonadal development and maturity is imperative for predicting the reproductive potential of fish, time and frequency of spawning and size at first maturity. Schizothorax plagiostomus plays a significant role in capture fishery in different Himalayan regions and is a demanding food fish. Several studies on reproductive biology of S. plagiostomus based on histology of gonads, gonadosomatic index, ova diameter and fecundity group it as asynchronous type, with long breeding period, spawning only once while some claim it to be a batch spawner. The present study attempted to correlate ovarian histology, gonadosomatic index, blood glucose concentration with serum vitellogenin as scorable protein biomarker, revealing that the species spawns at least in two or more batches during the same spawning season. Three isoforms of vitellogenin were identified after 2D gel electrophoresis and MS analysis i.e. Vitellogenin 1, Partial Vitellogenin 2 and 4. No expression was observed in immature phase from January to mid-February, thereafter serum samples showed significant expression of vitellogenin. However, the expression decreased in late-March and increased again in mid-April indicating species is a batch spawner; vitellogenin production seem to cease a little after spawning and increases before next batch of ovum are spawned.

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