Parasitism and Fatty Liver Disease in the Invasive Red Lionfish, Pterois Volitans (Linnaeus), Along the Gulf of Mexico

Invasive species are detrimental to both the economy as well as to environmental stability. One of the most successful to date is the red lionfish, Pterois volitans, which first invaded the western hemisphere around 30 years ago. Lionfish have decimated native fish populations at roughly 7,500 lbs. per acre per year, have no natural predators, and seem fairly resistant to parasitism. Few species (<50) of parasites have been found in lionfish. Not only is parasitic prevalence low in lionfish, but they also seem to exhibit resistance to the effects of fatty liver disease. This research provides an updated parasite survey and reports six species of parasites, three of which are parasite species reported for the first time in lionfish; (1) one Cymothoid isopod: Olencira praegustator, (2) one Corallanidae isopod: Excorallana truncata, and (3) an acanthocephalan: Serrasentis sagittifer. Overall parasite prevalence and intensity was low for all hosts, and were significantly higher in males. A baseline study of fatty liver analysis in lionfish revealed that >85% of examined fish displayed evidence of fatty liver disease, and most exhibited moderate degrees of disease. Sex, location, and standard length of lionfish did not play a significant role in degree of disease, though slight disease differences were observed among locations. Outward condition (i.e. skin/scale integrity, coloration, observed mass) of specimens observed in relation to fatty liver disease and parasitism seemed relatively unaffected.