Parasitism of dolfinfhishes, Coryphaena hippurus and Coryphaena equiselis, in the western Mediterranean (Balearic Islands) and central-eastern Atlantic (Canary Islands)

Abstract

A total of 648 dolphinfishes were examined for internal and external parasites in western Mediterranean (Balearic Islands) and central-eastern Atlantic (Canary Islands) waters in order to make a comparative study between the two areas. The specimens studied from the Mediterranean Sea was Coryphaena hippurus, with 62 large individuals captured from May to September and 497 juveniles captured from August to December. The specimens studied from the central-eastern Atlantic were 39 adult C. hippurus and 49 adult Coryphaena equiselis. Parasites were found in 70% of the fish examined, and represented a total of nine endoparasitic taxa: six digeneans (Class Trematoda, Subclass Digenea; Dinurus tornatus, Dinurus breviductus, Dinurus longisinus, Lecithocladium excisum, Bathycotyle branchialis and Hirudinella sp.), two nematodes (Class Nematoda, Order Spirurida; Philometroides sp. and Metabronema magna) and one acanthocephalan (Phyllum Acanthocephala; Rhadinorhynchus pristis). Seven crustacean copepod ectoparasites were identified: Caligus quadratus, Caligus productus, Caligus bonito, Caligus coryphaenae (Family Caligidae) and Euryphorus nymphae (Family Euriphoridae) were found in gill mucus masses or on the inner surface of the operculum, the lernaeopodid Neobrachiella coryphaenae (Family Lernaeopodidae) was attached to gill filaments and the pennellid Pennella filosa (Family Pennellidae) was anchored to fins and rays or, deeply, to muscular tissue and abdominal cavity. The relationships between feeding habits, parasite recruitment and parasite transmission were analysed, some ecological aspects of all the parasitic species are discussed, and some comments are made on parasite-host relationships.