Occurrence of Salmincola edwardsii (Olsson, 1869) and Salmincola markewitschi Shedko & Shedko, 2002 (Copepoda: Lernaeopodidae) on stream-dwelling salmonids in eastern Hokkaido, Japan, with observations on the morphology of the copepods

Abstract

Two copepod parasites, Salmincola edwardsii (Olsson, 1869) and S. markewitschi Shedko & Shedko, 2002, were collected from salmonids in eastern Hokkaido, Japan: these copepods were taken from whitespotted char, Salvelinus leucomaenis (Pallas, 1814), and brook trout, S. fontinalis (Mitchill, 1814) in the Nishibetsu River, and Salmincola edwardsii from southern Asian Dolly Varden, Salvelinus malma krascheninnikova Taranetz, 1933, in the Ichani River. Both whitespotted char and brook trout are new Japanese hosts for Salmincola edwardsii, and the two rivers represent new locality records for S. edwardsii and S. markewitschi. The Nishibetsu River is regarded as a new southernmost distribution limit of S. edwardsii in Asia and is also recorded as the first locality of S. markewitschi infecting wild salmonids in Hokkaido. The morphology of S. edwardsii and S. markewitschi is reported based on adult female specimens collected from the salmonids.