Anguillicolosis in the short-finned eel Anguilla australis: epidemiology and pathogenicity

A sample of 189 short-finned eels (Anguilla australis) from four geographical areas in New Zealand were examined for the occurrence of the swimbladder nematode Anguillicola spp. Anguillicola novaezelandiae was found in three of the four localities. Overall, the prevalence was low (<12%) as was the intensity of infection (between 1 and 5 parasites per infected eel). In comparison with data from Europe on a similar host-parasite system involving congeneric species (Anguilla anguillaAnguillicola crassus), it was concluded that the New Zealand short-finned eels do not greatly suffer from this infection. In particular, no effect of infection on body condition was detected. The damage caused by the parasite to the swimbladder was minimal, even in large silver eels about to undertake a long journey at great depth to reach their spawning grounds in the Pacific. A review of the available literature is presented to update the current knowledge of the distribution of Anguillicola infections in New Zealand.