HELMINTH-PARASITES OF THE DIGESTIVE-TRACT OF THE HARBOR PORPOISE PHOCOENA-PHOCOENA IN DANISH WATERS - A COMPARATIVE GEOGRAPHICAL ANALYSIS

Most studies of the helminth fauna of the harbour porpoise Phocoena ph ocoena have focused on taxonomy, associated pathologies and surveys re porting prevalence and abundance of the parasite species. This study ( 1) characterizes the helminth fauna of the digestive tract of the harb our porpoise in Danish waters and (2) examines the influence of some f actors structuring helminth communities within the host's geographical range. Seventy digestive tracts (oesophagus, stomachs, duodenal ampul la and intestines) were analysed. We found 5 helminth species (Anisaki s simplex, Hysterothylacium aduncum, Pholeter gastrophilus, Bolbosoma sp, and Diphyllobothrium sp.). Gastric ulcers associated with A. simpl ex were observed in 8 of the 28 porpoises infected with this parasite and gastric cysts produced by P. gastrophilus were observed in 2 of 70 porpoises analysed. No other pathologies were observed. The presence of H. aduncum and P. gastrophilus was the main difference between this study and a previous survey in the same area. Our data were compared with those of other analyses of helminth faunas from different harbour porpoise distribution areas. The geographical analysis suggested the presence of a strong local influence determining the helminth fauna, t he cestode Diphyllobothrium stemmacephalum being the only species whic h could be considered as a specialist of the harbour porpoise. The int estinal helminth community of this host represents the most depauperat e community recorded so far in a cetacean.