Sexual Reproduction of the Scleractinian Coral Merulina Ampliata in Southern Taiwan

Sexual reproduction of the scleractinian coral Merulina ampliata in Nanwan Bay, southern Taiwan was studied from 1990 to 1993. M. ampliata is a hermaphroditic broadcast spawner. Colony size at sexual maturity was 5.0–10.0 cm in diameter. Mature egg size and fecundity were 210 μm and 952 eggs cm^–2 yr^–1, respectively. Monthly changes of mean oocyte diameters and frequencies of colonies containing different stages of gametes indicated a brief annual gametogenic cycle. Oogenesis began in June 1991 and May 1992. Spermatogenesis began 1 mo later than oogenesis. Spawning occurred in September 1990 and 1991, and August and September 1992 during late summer to early autumn. Spawning of M. ampliata took place about 1 to 2 mo later in southern Taiwan than in Okinawa. The delayed reproduction of M. ampliata at the lower latitude (southern Taiwan) suggests that sea temperature may not operate as a primary factor controlling the reproductive seasonality of this species.