Research Article
Mahmoud Abdelghagffar Emam
Abstract
Forty mature catfish of both sexes (n=10 per season; 5 males and 5 females) were used to study the effect of different seasons on the histological and histochemical structure of the gonads. The histological results showed that both testes and ovaries of the catfish were degenerated during winter that was considered as a resting season of the catfish gonadal activity. Both testes and ovaries began to restore their intact and fully mature structure during spring and continue the same during summer where the testes show distended seminiferous lobules with all spermatogenic cells and spermatozoa also, the ovaries showed the different developmental stages including mature follicles therefore, both spring and summer were considered as spawning season of the catfish. During autumn, both testes and ovaries appeared as spent gonads where the testes showed many empty seminiferous lobules and the ovaries showed many atretic follicles therefore, autumn was considered as post-spawning or spent season. The results of Gonado-Somatic Index (GSI) were coincided with the histological structure of the gonads where they show peak value during spring and summer (spawning season) and showed the lowest value during winter (resting season).