Research Article: Gametogenesis and reproduction cycle of the sea urchin Echinometra sp. from the Northern Persian Gulf based on the histology and gonad indices

The sea urchin Echinometra sp. is a native species of the Persian Gulf. Despite its great ecological value, the reproductive biology of this animal has not been studied in the Persian Gulf. Therefore, the present study aimed to describe the annual reproductive cycle of this species from the Persian Gulf via gonadal tissue indicators. In the present study, approximately ۱۲۰ males and females were collected monthly (approximately ۱۰ samples/month) between February ۲۰۲۳ and January ۲۰۲۴ from the tidal zone of the Bushehr coast of the Northern Persian Gulf. The sex of the samples, different stages of sexual maturity, mean gonadal index, gonad coverage area, frequency of oocytes in different stages, and diameter of the oocytes were determined via gonadal tissue sections. Six stages of sexual maturity, including the repair, growth, premature, mature, spawning, and reabsorption stages, were detected in the gonads of the males and females. Only one annual reproductive cycle was identified for this species. In females, this cycle included a period of gametogenic activity (from December to June) and a spawning period of several months (from June to August), followed by a long period of recovery and sexual rest (from August to the end of December). In males, gametogenesis starts in October and lasts until the end of May. This period was followed by the spawning period from June to August and then a short period of recovery and sexual rest (September). It seems that a decrease in seawater temperature stimulates the start of the gametogenic cycle and high seawater temperatures stimulate the release of gametes of Echinometra sp. in Bushehr. In general, Echinometra sp. has a specific spawning season from late spring to early summer and is not able to spawn throughout the year.

کلیدواژه ها:

Sea urchin ، Echinoderms ، Reproductive biology ، Persian Gulf ، Echinometra sp.