Sexual reproduction cycle of the sea cucumber (Stichopus hermanni) in the coral reefs of Kish Island of Iran

Sea cucumber is commercially important in the world. Reproductive biology of Stichopus hermanni in the coral reefs of the Kish Island was investigated using 252 specimens. Morphology of the gonad of the sea cucumber species of the Kish Island was found to be similar to other species. We showed that the gonad color is an unreliable character for sex determination except in maturity stage. We reported the gametogenesis sequence of events and found a sex ratio of 1:1 for the species. The sequence begins late in winter and continues until summer. The active stage of gametogenesis coincides with increasing photoperiod and temperature. Very little spawning activity out of season was noticeable and the maximum spawning was seen in summer. Average body length at first maturity was found to be 310 mm and the diameter of mature oocytes was 200 um. Oocytes moved upward at a rate of 20-30mm per minute that confirms divers' reports of the abundance of developing S. hermanni embryos near the water surface