Author(s): Kandeel EK, Mahmad SZ, El-Ghitany AH and El-Ghobashy AE

Abstract: New Damietta shore is one of the important areas for collection of the clams as well as mullet, seabass and seabream larvae which are reliable for marine aquaculture in Egypt. The reproductive cycle of the clam; Donax variabilis (Say, 1822), in this shore was investigated during the period from May 2008 to July 2009. Reproductive maturity was estimated by assessment of gonad index and microscopic examination of gonadal smears and sections. The different stages of the reproductive cycle were characterized by histological examination. Six distinguishable gonad stages were determined in both male and female clams viz., early active, late active, ripe, partially spawning, completely spawning and spent stage. Both males and females showed synchronism in gonadal development. Spawning occurred between May and August with one major spawning phase. Donax variabilis is a dioecious species without sexual dimorphism or sex reversals. The ratio of males to females (1 M: 0.85 F) was statistically non-different from the theoretical sex ratio of 1:1 (X² = 8.70, P > 0.05).


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