Two Copepods Salmincola edwardsii and Salmincola markewitschi (Lernaeopodidae) Parasitic on Chars (Salvelinus spp.) Reared in a Salmon Museum, Northern Japan

Abstract

Specimens of two species of lernaeopodid copepods, Salmincola edwardsii (Olsson, 1869) and Salmincola markewitschi Shedko and Shedko, 2002, were collected from chars (Salvelinus spp.) reared in exhibition tanks of the Sapporo Salmon Museum, Hokkaido, Japan. Descriptions of these copepods are provided using the specimens. In 1988, adult females of S. edwardsii were found on the gills of southern Asian Dolly Varden, Salvelinus malma krascheninnikova Taranetz, 1933, and those of S. markewitschi in the buccal cavity of whitespotted char, Salvelinus leucomaenis (Pallas, 1814), Nikko char, Salvelinus leucomaenis pluvius (Hilgendorf, 1876), and brook trout, Salvelinus fontinalis (Mitchill, 1814). These copepods are considered to have been introduced to the museum in the late 1980s along with wild chars transported live from natural waters of Hokkaido. Adult copepods have been manually removed using forceps once or twice a year from reared chars, but such infrequent practices have not been effective to eliminate S. markewitschi, which was thus collected again in 2020. In contrast, S. edwardsii was completely eliminated by stopping rearing an infected population of southern Asian Dolly Varden, to which this parasite is host-specific.