INFLUENCE OF HAEMOBAPHES-CYCLOPTERINA AND H-INTERMEDIUS (COPEPODA) ONARCTIC COD (BOREOGADUS-SAIDA) AND TIDEPOOL SCULPINS (OLIGOCOTTUS-MACULOSUS), RESPECTIVELY

A study was conducted to determine the prevalence and effects of two s pecies of blood-feeding copepods on their definitive fish hosts, viz. Haemobaphes cyclopterina parasitizing Arctic cod (Boreogadus saida) an d H. intermedius infecting tidepool sculpins (Oligocottus maculosus). Infected and uninfected Arctic cod and tidepool sculpins were captured by SCUBA and dip net in the northwest Atlantic and northeast Pacific, respectively. Biological variables such as condition factor, hepatic somatic index, gonadal somatic index, and haematocrit were compared be tween the two groups of Arctic cod of both sexes, whereas only conditi on factor was compared in the two groups of sculpins of both sexes. Pr evalence of H. cyclopterina (8%) was considerably lower than that of H . intermedius (46%). This difference is probably associated with the h osts' behaviour, as the Arctic cod is pelagic whereas the tidepool scu lpin is restricted to the littoral zone, where infections are probably acquired. Infected Arctic cod of both sexes had significantly lower c ondition factor, hepatic and gonadal somatic indices, and haematocrit than non-parasitized fish. Only females harboured Large numbers of the parasite and showed even more dramatic changes than the corresponding groups. The growth period of H. cyclopterina on Arctic cod from the t ime of infection to the fully developed egg sac stage is probably abou t 6 months. In tidepool sculpins, condition factor was significantly l ower in infected than in uninfected fish. These results, especially fo r the Arctic cod, parallel those reported for gadoid fish following in fection with haematophagous species of Lernaeocera that impair growth and reproduction.