No apparent effects of the buccal cavity attaching parasite, Salmincola sp. (Copepoda: Lernaeopodidae), on a stream salmonid: a mark-recapture study

We evaluated the effects of a buccal cavity attaching Salmincola sp. on white-spotted charr Salvelinus leucomaenis by mark-recapture method to compare body condition, growth, and apparent survival within a headwater stream of the Shiodomari River, Hokkaido, Japan. Prevalence was 13.1–15.5% and the mean intensity was 1.2–1.3 parasites per individual (max = 4). Infected fish were significantly larger than non-infected fish and larger fish had significantly higher apparent survival, but no significant difference was detected in body condition, growth, or apparent survival between infected and non-infected fish. Prevalence and intensity in natural streams may be too low to cause harmful effects on host species.