Invasive Species Compendium

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Abstract

Helminths as biological tags for franciscana (Pontoporia blainvillei) (Cetacea, Pontoporiidae) in Argentinian and Uruguayan waters.

Abstract

The helminth fauna of 46 franciscana or La Plata dolphins (Pontoporia blainvillei) from Necochea and Claromecó (Argentina) was compared with previous records from Punta del Diablo (Uruguay) in order to establish whether dolphin populations mixed freely between localities or formed isolated stocks. Six helminth species were found in the Argentinian dolphins: Polymorphus cetaceum, Polymorphidae sp., Hadwenius pontoporiae, Pholeter gastrophilus, Anisakis simplex and Contracaecum sp., of which Contracaecum is a new geographical record. Six species from this host have also been listed from Uruguay: Trematoda sp., Polymorphus cetaceum, Anisakis typica, Contracaecum sp., Procamallanus sp. and a cestode larva. The presence of 2 species of Anisakis could be related to the geographical distribution of each species. Differences in prevalence among the least common helminth species (Pholeter gastrophilus, Procamallanus and unidentified trematodes and cestode larvae) and changes in the intensity of infection of Polymorphus cetaceum and Hadwenius pontoporiae may be explained by environmental differences but temporal causes cannot be discounted. The overall results suggest that Pontoporia blainvillei may be sedentary, at least from spring to early summer, with separate stocks despite the proximity of the localities.