High Prevalence of the Copepod in Steelhead Trout in Lake Ontario Following its Recent Invasion.

(Dana, 1853) (Subclass Copepoda: Family Lernaeopodidae) is known to parasitize salmonids of the genus including (rainbow trout), (chinook salmon), and (coho salmon). These 3 salmonids have been introduced to the Great Lakes intermittently since the mid-1800s. As we demonstrate here, the introduction of these salmonids to the Great Lakes was followed, at some point, by the introduction of their parasitic gill copepod, .