Octocoral diseases and invasive species in the Tropical Eastern Pacific

Imagine going to the field to gather samples of your model species and find it diseased and dying. A fungal-like disease, similar to aspergillosis commonly affecting Gorgonia in the Caribbean, recently appeared for the first time in the Eastern Tropical Pacific of Colombia, affecting a number of Pacifigorgia seafans. We haven’t entirely understood the diversity of Pacifigorgia spp. and they have been swept by disease in some regions of Colombia. We have witnessed disease-induced mass mortalities at Gorgona and Malpelo Islands during 2008 and 2009, which prevalence in seafans was corroborated during 2010. The disease also appeared at the Choco coast in 2009. The different outbreaks corresponded to high temperature anomalies according to satellite sea surface temperature. This adverse situation is exacerbated with the appearance of the invasive octocoral Carijoa riisei. This invasive species has been observed in the area for over a decade ago but its fast proliferation and seafan overgrowth appear to emerge recently. C. riisei is displacing natural communities comprising a serious threat to all gorgonian corals in these areas. A developing hypothesis is that the prevalence of the disease, as well as the invasive species superiority, could be related to rising seawater temperatures. Our preliminary observations suggest that seafan species overgrown by C. riisei appear also more susceptible to develop fungal diseases.

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