Occurrence and distribution of the parasitic copepod Leposphilus labrei on corkwing wrasse (Crenilabrus melops) from Mulroy Bay, Ireland.
Corkwing wrasse (Crenilabrus melops: Labridae), used to control ectoparasites on sea-farmed salmon, were found to contain the copepod parasite Leposphilus labrei (Philichthyidae) within the lateral line. Prevalence was 30.7% in 6,270 wrasse examined from Mulroy Bay, Ireland. Significantly more males than females or juveniles were infected; this appears related to size at age, as prevalence increases above 100 mm total length. Intensity was normally unity and the parasite showed a significant preference to infect the left rather than the right side of male wrasse. It is suggested that this preference is due to asymmetric fish locomotion, equivalent to "handedness."