Two Species of Trichodina (Ciliophora: Peritrichida) from Cultured Flatfishes (Pleuronectiformes) in Atlantic Canada

Air-dried smears of trichodinids were collected from cultured marine flatfishes of the families Pleuronectidae and Scophthalmidae at 2 localities in Atlantic Canada and stained using Klein's dry-silver impregnation technique to reveal the morphology of the adhesive disk. Two species were identified: Trichodina jadranica from the skin of captive broodstock of Pleuronectes americanus, Limanda ferruginea, Hippoglossus hippoglossus, and Scophthalmus aquosus and Trichodina hippoglossi from the skin of juvenile and broodstock H. hippoglossus. The former parasite has an extensive distribution in marine seas worldwide and has broad host specificity. The latter parasite is known only from the North Atlantic Ocean and has been found only on H. hippoglossus. This study represents the first confirmed identifications of Trichodina from pleuronectiform fishes in Atlantic Canada and the first reports of these species in Canadian waters.