Effects of oil contaminants on survivorship of larvae of the scleractinian reef corals Acropora tenuis, Goniastrea aspera and Platygyra sinensis from the Great Barrier Reef

Previous studies have shown that oil contaminants may seriously harm scleractinian corals, with effects ranging from sub-lethal responses including reduced reproductive success, to mortality of corals. However, information on the specific toxicity of oil and dispersed oil to coral larvae is very limited. This study examined the effects of the water accommodated fraction (WAF) of fuel oil, dispersed fuel oil, and Ardrox 6120 dispersant on the survivorship of Acropora tenuis, Goniastrea aspera, and Platygyra sinensis scleractinian coral larvae. The results showed that dispersed oil and dispersant are far more toxic than undispersed oil WAF to the survivorship of these larvae. The concentrations of dispersed oil and dispersant causing high levels of mortality were well within the range that may be expected in the vicinity of an oil slick that has been chemically dispersed. These results clearly demonstrate that coral reproductive success will be significantly impaired if coral larvae encounter chemically dispersed oil or dispersant. Therefore, dispersants should not be used in the vicinity of coral reefs during coral spawning episodes or the subsequent planktonic larval development phase.