LUNGWORM (OTOSTRONGYLUS-CIRCUMLITUS) INFECTIONS IN RINGED SEALS (PHOCA-HISPIDA) FROM EASTERN ARCTIC CANADA

Otostrongylus circumlitus, a metastrongyloid nematode found in the lun gs of ringed seals (Phoca hispida) and other pinnipeds, may affect the health of seals and reduce diving capacity. Of five sites sampled in eastern Arctic Canada (190 seals examined), Salluit, Que., is an impor tant enzootic zone (prevalence 48.2%, n = 27). Maximum intensity of O. circumlitus was 32 worms. Infection is restricted to young-of-the-yea r seals and may have an impact on recruitment of the population. Local geographic conditions may influence transmission of the parasite and thus prevalence and intensity of O. circumlitus among populations of r inged seals. No condition index used showed any significant relationsh ip to infection, but prevalence and intensity were related to sternal blubber thickness (0.01 <p < 0.05) indicating that this parasite may h ave an effect on the physical condition of seals. Otostrongylus circum litus may have an indirect effect on seals by modifying their diving b ehavior. Severe infections may lead to death, but light infections cou ld be lost after a certain time with subsequent development of protect ive immunity.