Meeting Abstract
Environmental phenomena such as temperature, photoperiod, tidal cycle and lunar rhythm act as external cues that stimulate the reproductive activity of marine organisms. In this study, we report the annual and lunar reproductive cycles, and changes in nutritive phagocytes (NPs) in relation to gonadal maturation of Atlantic sea urchin (Arbacia punctulata, a primeval species). Monthly and weekly changes in gonadal development/maturation were observed histologically. In male, the testicular lobules were densely packed with sperm from June to August. In female, on the other hand, mature eggs first appeared in some ovaries in May, numerically increased from June to July, and decreased in August. During gametogenesis, NPs in both sexes were depleted from June to August. Histological observations revealed that the gonad developed synchronously around the new moon. Collectively, our results suggest that A. punctulata spawns several times during the summer months according to lunar cycle in the Gulf of Mexico. This is the first report, to the best of our knowledge, on annual and lunar reproductive rhythms of Arbacia species in the Gulf of Mexico, a marginal sea in the Atlantic Ocean surrounded by the North American continent.
