Marine & Environmental Sciences Faculty Proceedings, Presentations, Speeches, Lectures


Internal Parasites of Selected Mesopelagic Teleosts in the Offshore Tropical Western North Atlantic Ocean

Event Name/Location

30th Annual Meeting of the Florida Chapter of the American Fisheries Society, Altoona, Florida, February 16-18, 2010

Document Type

Conference Proceeding

Publication Date



Atlantic Ocean Internal parasites have the potential to both inhibit nutrient uptake and stimulate an inflammatory response in the host. Of the many potential sources of cryptic mortality and morbidity in fishes, the effects of internal parasites are perhaps the least studied. The internal parasite fauna of the mesopelagic teleost species snake mackerel (Gempylus serpens), oilfish (Ruvettus pretiosus), lancetfish (Alepisaurus ferox and A. brevirostris), and escolar (Lepidocybium flavobrunneum) are described from the South Atlantic Bight in the western North Atlantic. Host specimens were obtained as incidental bycatch aboard commercial pelagic longline vessels. All specimen fishes were preserved on ice or frozen whole, and parasites recovered at laboratory dissections were preserved in 70% ETOH. To date, 122 mesopelagic teleost fishes have been sampled, yielding well over 200 individual parasite specimens. Parasite phyla found to date include nematodes (roundworms), trematodes (flukes), acanthocephalan (thorny-headed worms), and cestodes (tapeworms). Total internal parasite loads were compared against the size (length and weight) of the host; however, results show no relationship between these factors. Each of these co-occurring mesopelagic species shows a different parasite complex. G. serpens appears to show the lowest incidence of parasitism yielding predominantly nematodes with a small amount of trematodes. A. ferox has shown nearly one hundred percent parasitism yielding trematodes. L. flavobrunneum have been shown to host nematodes, cestodes, and acanthocephalans. R. pretiosus have been shown to host mostly nematodes. These results establish methodologies and baseline values for expected internal parasite load and species compositions for mesopelagic teleost hosts. As preliminary data has shown that the parasites in these hosts are not species specific, other pelagic and mesopelagic fishes may be susceptible to similar infestation. Future research is suggested to ascertain if commercially valuable, co-occurring pelagic fishes may not also be at risk for similar infestation patterns.





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