Susceptibility of Channel Catfish (Ictalurus punctatus), Blue Catfish (Ictalurus furcatus), and Their Commercially Cultured Hybrid to Metazoan Parasite Infection in Earthen Pond Aquaculture

ABSTRACT: We herein document the metazoan parasite component communities of channel catfish (Ictalurus punctatus), blue catfish (Ictalurus furcatus), and their commercially cultured hybrid (female I. punctatus × male I. furcatus) communally stocked as parasite-free fingerlings into each of 3 experimental earthen ponds (each pond harbored channel catfish, blue catfish, and hybrid catfish). The fundamental objective of this work was to test the hypothesis that hybrid catfish exhibit less susceptibility to infection by metazoan parasites than do their parental species. Fingerlings of each catfish species from each pond were parasitologically examined monthly for 1 yr. A total of 112 channel catfish, 74 blue catfish, and 209 hybrid catfish were necropsied; collectively resulting in the detection of 14 metazoan parasite species. Channel catfish had the most diverse component community (12 species: 3 myxozoans, 2 monogenoids, 3 cestodes, 1 nematode, 1 unionid, and 2 copepods) followed by hybrid catfish (11 species: 3 myxozoans, 2 monogenoids, 2 cestodes, 1 nematode, 1 unionid, and 2 copepods) and blue catfish (6 species: 1 myxozoan, 2 monogenoids, 2 cestodes, and 1 copepod). These results do not support the assertion that hybrid catfish are demonstrably more resistant to parasitic infection than either parental species. New host–parasite records herein comprise Corallotaenia intermedia (Fritts, 1959) Freze, 1965, and Corallotaenia parafimbriata (Befus and Freeman, 1973) Scholz, de Chambrier, Mariaux, and Kucha, 2011 for channel catfish; Henneguya sp., C. parafimbriata, and Neoergasilus japonicus (Harada, 1930) Yin, 1956 for blue catfish; and Henneguya adiposa Minchew, 1977, Henneguya bulbosus Rosser, Griffin, Quiniou, Khoo, and Pote, 2014, Ligictaluridus mirabilis (Mueller, 1937) Beverley-Burton, 1985, Ligictaluridus pricei (Mueller, 1936) Beverley-Burton, 1984, Essexiella fimbriata (Essex, 1928) Scholz, de Chambrier, Mariaux, and Kucha, 2011, C. parafimbriata, Spiroxys sp., Pyganodon sp., N. japonicus, and Achtheres sp. for hybrid catfish. To our knowledge, this is the most extensive parasitological study of this particular hybrid catfish, or any hybrid catfish, published to date.