Movements of satellite tracked Magellanic penguins (Spheniscus magellanicus) in a wintering area in southern Brazil

Food availability and oceanographic conditions drive the distribution and movement of marine vertebrates. Tracking efforts towards seabirds usually focus on their breeding period, tagging adults in colonies. In this study, we tracked four juvenile and one adult Magellanic penguin (Spheniscus magellanicus) with satellite transmitters. These individuals were caught incidentally in gillnets and were tagged at sea, with the exception of the adult that was rehabilitated and released on the beach. The penguins were tracked in their wintering grounds, where behavior and oceanographic characteristics of the area used were determined. All five birds remained along the coast of southern Brazil and Uruguay in neritic waters up to 10 km offshore and 50 m in depth. The four juveniles used a mean area of 1,426 km2, travelling on average at 7.4 km/h. The high turning angles observed and mean sinuosity of 2.46 indicated that the penguins were foraging. The adult penguin covered an area of 1,033 km2, at a mean speed of 4.6 km/h, and with low sinuosity (0.43), which is suggestive of either travelling movements or an experienced hunter who needs a few turning angles to forage. The adult travelled 538 km in total, reaching a maximal distance of 465 km. Locations were obtained over a period of 7–10 days, and all five penguins remained in waters of the coastal branch of the Malvinas Current, an area characterized by cold sea surface temperatures (SST, mean = 13.4 °C) and high primary productivity. Salinity values (34.06 PSU) were also typical of the Malvinas Current and were influenced by the La Plata River plume, whose waters are low in salinity and nutrient rich. All five penguins remained near the coast probably because these waters are rich in nutrients, and carry the penguins' main prey, the Argentine anchovy (Engraulis anchoita). Regarding conservation concerns involving these penguins, we highlight the current management of the anchovy fisheries and the development of offshore windfarms that could potentially cause major disturbances to the penguins’ foraging habitat. The establishment of the Albardão National Park in the nearshore area used by the penguins is highly desirable for the protection of the species and their feeding resources.