Helminth fauna Magellanic Penguins in a colony of Península de Valdés, Chubut, Argentina

LAURENTI, S.; PAZOS, G. E.

Coquimbo, Chile

Congreso; IV International Penguin Conference; 2000

Studies linking the behaviour and feeding of Magellanic Penguins (Spheniscus magellanicus) were carried out at a colony in the north of Peninsula Valdés (42° S-63° W). Moribund and recently-death specimens were examined to determine the taxonomic composition of the parasitic fauna harboured in these birds acting as the definitive host (Hd). The digestive tracts of 15 penguins of different ages were analysed (8 adults, 2 juvenile immature and 5 chicks) collected during the reproductive season (November-April). The objective of this work was to evaluate the extent to which the dietary habits of the bird affect the structure of associated parasites. In particular, long-term resident parasites might allow speculation as to the feeding habits of the birds during the seasonal migrations. Viscera were conserved by freezing at –20°C. The digestive tract was separated into oesophagus, stomach and at least ten sections of intestine, each 20 cm long. In adults, as well as in chicks, larvae and adult Nematodes Contracaecum pelagicum and Cosmocephalus obvelatus, were located in the oesophagus and stomach. Cestodes of the genus Tetrabothrius.and Digenea of the genus Cardiocephaloides were found in the upper small intestine as were Acanthocephalans of the genus Corynosoma although these parasites only occurred in 5 birds. In general, the mature host showed a parasitic load similar to that of the chicks, although the specific diversity was lower. The results obtained allow us to hypothesize that Magellanic Penguins are primarily stenophagous during November-January (Scolaro et al. 1984). Stenophagy favours the decrease both of parasitic load and parasite species wealth, while euryphagy (February-March) results in an increase in these parameters.