Reproductive patterns of Scleractinian corals on Singapore's reefs

Abstract

Sampling of Porites lutea and Platygyra sp. over fourteen months in Singapore revealed similar, markedly seasonal patterns of gametogenesis, with spawning predominantly in April. Among an assemblage of Acropora a high proportion of species also contained mature gametes in the same month, and twenty-four scleractinian species were observed releasing gametes during discreet spawning events in March 2002 and April 2003. Concurrence of spawning times with a rise in sea surface temperature indicated that this factor might be the seasonal cue for gamete maturation and spawning. These findings reveal that multi-species coral spawning is not restricted to reefs at higher latitudes. A manipulative field experiment was conducted to investigate the effects of fragmentation and transplantation on reproduction in Goniopora corals. Transplants within the same site and depth were unaffected by fragmentation, whereas transplants to a more disturbed site and to greater depth contained significantly fewer and smaller eggs after one year.