Helminth parasites from North Pacific anadromous chinook salmon, Oncorhynchus tshawytscha, established in New Zealand

Abstract

The following marine species of parasites are reported from the gastrointestinal tract of pre-spawning chinook salmon, Oncorhynchus tshawytscha, taken in the Rakaia River, New Zealand: the digeneans Derogenes varicus, Lecithocladium seriolellae, Para-hemiurus sp., and Tubulovesicula angusticauda; and a tetraphyllidean metacestode, possibly of the genus Phyllobothrium. A small larval nematode tentatively assigned to the genus Contracaecum was found in the intestine and may be either of marine or freshwater origin. All are species acquired in the new environment of the salmon, descendants of stock introduced from California.