Pollution is a potential factor in the disappearance of the species although its consequences on coral are actually not well known. According to the coral fishers, the species does not seem especially sensitive to pollutants; collections have been made near the drainage-pipes at Cortiou , Marseilles. Rivoire (1987) recorded a high percentage of dead colonies off La Ciotat between 50and 150 metres depth on eastern slopes, exposed to the Ligurian current. This important mortality was connected with the presence of heavy metals and hydrocarbons (Harmelin et al., 1991). Although pollutant action on corals is little known, the effect of micro-particles from marine dredging or construction, for example, seems extremely noxious, tending to suffocate the colonies.
Other examples of mortality were noticed at the end of the 1990s. Unknown causes provoked important mortality in gorgonians and other invertebrates.