The taxonomy of Gyrodactylus (Monogenea) parasitizing certain salmonid fishes of North America, with a description of Gyrodactylus nerkae n. sp.

Abstract

Specimens of Gyrodactylus Nordmann, 1832, both newly collected and deposited type material, from cultured and wild salmonid fishes from various localities in North America, are compared and five species are recognized: G. salmonis Yin and Sproston, 1948 status emended, on Salmo clarki, S. salar, S. aguabonita, S. gairdneri, S. trutta, Salvelinus fontinalis, S. namaycush, and Oncorhynchus kisutch from several localities throughout the continent; Gyrodactylus nerkae n. sp. on O. nerka from Vancouver Island; G. colemanensis Mizelle and Kritsky, 1967 on Salmo gairdneri from California, Arkansas, and insular Newfoundland, S. fontinalis from Nova Scotia and Ontario, and S. trutta, S. namaycush, and S. fontinalis × S. namaycush from Ontario; G. avalonia Hanek and Threlfall, 1969 on S. gairdneri from Nova Scotia; and G. brevis Crane and Mizelle, 1967 on S. gairdneri from California. Gyrodactylus salmonis, G. nerkae, and G. colemanensis are considered specific to salmonid fishes, whereas G. avalonia and G. brevis are considered "accidental" infections, acquired from nonsalmonid fishes. A diagnostic key to the five species is provided and gyrodactyliasis, as a disease of cultured salmonids in North America, is discussed briefly.

Gyrodactylidae et Gyrodactylose des Salmonidae

“…G. ava/on/a Hanek etThrelfall, 1969 is most likely a memberof the G. arcuatusgroupand G. brev/sCraneetMizelle, 1967, certainly a memberof the subgenus G. (Gyrodactylus). Although the two species are described from salmonids, they are not included here because of their "accidentai" présence on salmonids (see CONE et al, 1983).…”

“…Saimo gairdneri) and the locality a fish farm in California. About 15 years later, CONE et al (1983) reviewed the Gyroc/acfy/us species on salmonids in Canada and USA. For their présentation they used spécimens collected from wild and cultured salmonid fish across the North American continent and made a comparative taxonomic analysis of the spécimens.…”

“…tn the collection, only five species were recognized. Three of them seem to be spécifie to salmonid hosts : G. nerkae Cone, Beverley-Burton, Wiles, McDonald, 1983. G. salmonisYln et Sproston, 1948and G. colemanensis Mizelle et Kritsky, 1967.…”

“…CONE et al (1983) could establish only three species, spécifie to salmonid hosts in North America: G. nerkae, G. salmonis and G. colemanensis.…”

“…Thus in Norway, salmon and trout were investigated (TANUM, 1983;MO, 1983). CONE et al (1983) analysed and reviewed North American gyrodactylids on salmonids, ERGENS (1983) analysed and described Gyrodactylus species on salmonids in Eurasian f reshwaters and LUX (1990) contributed with new data about gyrodactylids on salmonids in Germany. In the discussion on spreading of G. salaris, the Baltic area became a burning question and Swedish salmonid farms and rivers were investigated (MALMBERG et MALMBERG, 1991) and Gyrodactylus species from Finnish salmonid farms were discriminated (RINTAMÀKI, 1989;MALMBERG et MALMBERG, inpress).…”