Intestinal parasites of Franciscanas, Pontoporia blainvillei (Cetacea: Pontoporiidae) from Provincia de Buenos Aires, Argentina.

MARIGO, JULIANA; NEGRI, MARÍA FERNANDA; PASO VIOLA, MARÍA NATALIA; SANTOS, C. P.; CAPPOZZO, HUMBERTO LUIS

San Pablo, Brasil

Congreso; XVI Encontro da Associacao Brasileira de Veterinarios de Animais Salvagems; 2007

Asociación Brasilera de Veterinarios de Animales salvajes

Pontoporia blainvillei Gervais & d’Orbigny, 1844 is a small cetacean, common named franciscana, which is endemic to South Atlantic waters, occurring from Espírito Santo State, Brazil (18º25’S) to Peninsula Valdez, Argentina (42º35’S). The trematode Synthesium pontoporiae (Raga, Aznar, Balbuena & Dailey, 1994) was previously referred parasitizing the small intestine of P. blainvillei along its distribution area. In the present study, we analyzed the intestines of 17 franciscanas accidentally captured in fishing nets from three localities south of Provincia de Buenos Aires, Argentina. During the necropsy the intestines were removed, fixed in formalin and changed to alcohol for storing to be analyzed in the laboratory. The small intestine was divided in five equal-sized sections; these portions were opened with scissors inside a plastic tray, the contents were washed in a sieve (mesh =150mm) and examined under a stereomicroscope. The helminths collected wer e counted and stored in 70% alcohol. The mean length of the small intestine was 30m (±6). Dolphins were mostly juveniles with total body length varying from 98 to 158cm with average of 123cm (±17) and ages from 1 to 13 years, 3 years in average. All parasites were found in the first portion of the intestine, close to the stomach. A total of 2300 adults of Synthesium pontoporiae were obtained. The prevalence of S. pontoporiae was 88% and the number of parasites per host varied from 5 to 450 with mean intensity of 153 (±151). Fish consumed by these franciscanas were Cynoscion guatucupa, Trachurus lathami, Engraulis anchoita and Raneya fluminensis. The high prevalence and mean intensity of S. pontoporiae were similar to previous studies in Argentinean waters and this may be related to seasonal changes associated to fransciscana’s diet. The study of the ecology of these parasites may contribute significantly to their use for stock identification.