Reproduction Patterns of Scleractinian Corals in the Central Red Sea

摘要

Early work on the reproductive seasonality of corals in the Red Sea suggested that coralsexhibit temporal reproductive isolation, unlike on the Great Barrier Reef where manyspecies spawn in synchrony. More recent work has however shown high synchrony in thematurity of gametes in Acropora species, suggesting multi-specific spawning is likely tooccur in the Red Sea. In this thesis I investigate the patterns of coral reproduction in thecentral Red Sea. The spawning season in the central Red Sea lasts four months, fromApril to July and spawning occurs on nights around the full moon. During this periodAcropora species show a peak of spawning in April, with some species spawning againin May. The level of synchrony, quantified with a spawning synchrony index, iscomparable to other locations where multi-specific spawning has been reported.Observations over two consecutive years show that the synchrony of spawning was lowerin spring 2012 than in spring 2011, and thus that spawning patterns are variable from oneyear to the other. Coral settlement patterns on artificial substrata confirmed a mainspawning season in the spring but also supported reproductive data suggesting that somePorites spawn in October-November. Settlement was studied over 2.5 years on a reef,which had suffered recently from high mortality after a local bleaching event. Settlementappeared low but post-bleaching studies from other locations indicated similarabundances and showed that recruits generally did not increase until 5 years after thebleaching event. Abundance of juvenile corals however started to increase significantlythree years after the bleaching. Successful recruitment, although low suggests that thecoral assemblage on the affected reef will most likely recover as long as it is not affectedby another disturbance.