ABSTRACT
The toxicity of the Zoanthids Palythoa toxica, and Palythoa tuberculosa, which contain palytoxin has led to investigations of toxicity in the Alcyonacea. A number of species of soft corals have now been examined in detail and ranked according to their ichthyotoxicity towards Gambusia affinis. An extract of each coral was fractionated to yield a lipophilic, and a water-soluble fraction, and the relative toxicities of those fractions were determined. Studies on a Sarcophyton species revealed that the concentration of the major diterpenoid metabolite was significantly higher in the actual coral polyp than in the surrounding coenenchyme tissue; although the presence of spicules alters the effective amount of tissue present in each case, significant concentration differences are still evident after correction for the weight of spicules present. Ten pure compounds which were some of the major terpenoid components from the nine octocoral species under investigation were also tested for ichthyotoxicity at the 5 ppm level using ethanol solution diluted with conditioned freshwater.
