SEASONAL CHANGES IN THE OVARY AND PAS +VE CYANOPHILS OF THE PITUITARY IN CHANNA STRIATA BL. (TELEOSTEI)

Abstract

The ovarian cycle of snake-head, Channastriata is divisible into, (1) Pre-spawning (Mar.-May); (ii) Spawning (Jun.-Aug), (iii) Post-Spawning (Sep.-Nov.) and (iv) Preparatory (Dec.-Feb.) seasons. The co-relative changes of PAS +vecyanophils of the pituitary gland parallel the fluctuations of gonosomatic index (GSI) and the ova diameter. During pre-spawning season, a quantitative increase in PAS +ve cells and their secretory activity is followed by increase in ovarian weight and vitellogenesis. The peak of GSI (6.4) and ova diameter (1.12mm) occurs in June, when the spawning begins. Oogenesis commences in September when the activity of PAS +ve cells is at the lowest level. Ovarian recrudescence starts in February and the process of vitellogenesis continues during pre-spawning season. The pattern of oocyte growth in C. striata is "Group Synchronous type. Seasonal changes in PAS +v cyanophils during different phases of ovarian maturity idicate their gonadotropic role. This information may prove quite useful for the artificial culture of this species.