The Reproduction of the Red Sea Coral Stylophora pistillata. II. Synchronization in Breeding and Seasonality of Planulae Shedding

Synchronization in breeding and seasonality of planulae shedding of the hermatypic coral Stylophora pistillata were studied in the northern Gulf of Eilat, Red Sea. Gonads were histologically examined every month, for approximately 2 years. Planulae larvae were collected in situ over 5 years. In contrast to the results of Atoda (194fa) in Palao, who claimed lunar periodicity of planulation, no correspondence with lunar periodicity was observed in the population of the Gulf of Eilat. S. pistillata has a long period of reproduction lasting approximately 8 months (from December to July). During the reproductive period synchronization in breeding exists in different branches within a single colony. However, no such synchronization has been found among colonies within the population. In a reproductive colony, all polyps on the mid part of a branch contained gonads, while only a few polyps from the tips of the branches contained genital cells. Reproduction in S. pistillata begins In colonies of size groups f = 1.51 to 2.00 cm. More than 50 O / O of the population was found to be in reproduction in the size groups = 2.01 to 2.50 cm. In the first year of reproduction, the vast majority of the population contains male gonads only. With an increase in size, there is a tendency of an increase in the percent of hermaphroditic colonies within the population. In the largest colonies (F> 5.50 cm) more female gonads per polyp are developed compared with smaller size groups (F< 5.50 cm). High variability was found in the number of extruded planulae (24.2 42.5 per coral head, per night). From the view of point of reproductive effort, S. pistillata exhibits 4 major stages in its life history: very young or non-reproductive colonies, first-year reproductive colonies (mainly males), hermaphroditic mature colonies, and hermaphroditic oldest colonies. Differences in the life history of the Red Sea and Palao populations and the fact that S. pistillata is a brooding speciesin contrast to a theoretical expectation of a typical r-strategistare discussed.