Host–parasite relationship in Magellanic Penguins (Spheniscus magellanicus) during their long northward journey to the Brazilian coast

Abstract

The Magellanic Penguin Spheniscus magellanicus is one of the main seabird predators in the western South Atlantic. This species presents an opportunist feeding behaviour and its diet, as well as its parasite fauna, varies geographically depending on available prey and intermediate hosts. Despite thousands of Magellanic Penguins being found dead every year in southern Brazil, little attention has been given to their parasite–host interactions in this area. In this context, the aim of the present study was to assess the relationship between Magellanic Penguin diets and gastrointestinal helminth fauna at different age classes and body conditions in southern Brazil. To this end, the gastrointestinal tracts of 63 Magellanic Penguins found dead in 2013 and 2014 were examined. All individuals were parasitized by at least one species and only one penguin did not contain any food remains. A total of 138,209 helminths comprising eight species were found. Moreover, 12 prey species were recorded, including six fish and six cephalopod taxa. The helminth component community composition of juvenile penguins was similar to that of adults but the structure differed according to penguin age class. Cephalopod and crustacean prey species were significantly more frequent in juveniles compared to adults. Adults preyed mainly upon fishes. It was evident that lean individuals, both juveniles and adults, are more intensely infected in southern Brazil. Therefore, the high abundance of helminth parasites and the consumption of less energy-efficient prey cannot be ruled out as contributory factors to the high mortality of this species, mainly lean juveniles, in this area.