Prevalence and seasonal variation of Olpidiopsis porphyrae (Oomycota) infecting red algal Bangiales from the Southern Pacific.

The Bangiales are one of the most common seaweeds in sub-Antarctic and Southeastern Pacific upper intertidal habitats. Here we report records of an 'olpidioid' marine obligate parasite infecting Bangiales between 39°20′–41°44′S in the Southeastern Pacific for the first time. The disease resembles the 'Olpidiopsis blight disease' reported for farmed Bangiales in Japan and Korea and wild Pyropia from Scotland morphologically and developmentally. The Chilean isolate infects commercial Chilean laver or 'luche' (Porphyra sensu lato) and Bangia sensu lato from wild populations in the Southeastern Pacific. Phylogenetic markers (cox2, 18S) identify it as Olpidiopsis porphyrae. We relate the occurrence of this pathogen to both 'luche' fisheries in Chile and the potential consequences for its emergent aquaculture in the Southeastern Pacific. Highlights: The parasite Olpidiopsis porphyrae (Oomycota) is reported in Chile and the Southeastern Pacific for the first time. O. porphyrae infects Chilean Porphyra and Bangia sensu lato. The prevalence of O. porphyrae is very variable between populations, and highly seasonal in a locality of Southern Chile. [ABSTRACT FROM AUTHOR]