Parasite component community of a mangrove-dwelling killifish species

Macroparasite species infecting the mangrove rivulus fish (Kryptolebias marmoratus) are relatively unknown and have never been previously described in Florida. We collected 20 specimens from a wild population using cup traps deployed in the mangroves along a transect and then examined each fish for external and internal macroparasites. There was 100% prevalence of Ascocotyle sp. digenean trematode metacercariae in the bulbus arteriosus, and 65% prevalence of Octospiniferoides chandleri (Acanthocephala) in the gut, one Contracaecum sp. nematode found embedded in muscle tissue, and one copepod (family Caligidae) found on a fin. Longer and heavier fish had significantly higher Ascocotyle sp. abundance, and the relative condition factor of the fish host was negatively correlated with Ascocotyle sp. abundance, but not O. chandleri abundance. Our study is the most comprehensive survey of the macroparasite component community in K. marmoratus and can inform future studies about parasites that may impact other mangrove killifish species.