First record of endoparasites in Magellanic penguin (Spheniscus magellanicus) nest soil in one of the southernmost breeding colonies at Martillo Island, Tierra del Fuego, Argentina

Abstract

This study provides the first comprehensive analysis of endoparasite diversity associated with Magellanic penguins (Spheniscus magellanicus) at the southernmost extent of their distribution, within the Beagle Channel , Argentina. Using nest sediment sampling, multiple parasite genera were identified, including Corynosoma, Cosmocephalus, and Contracaecum, alongside various taxonomic groups like trematodes, cestodes, and acanthocephalans. These findings indicate that penguins in this colony are exposed to a wide range of parasites, with nematodes being the most prevalent. Endoparasite abundance was higher during chick rearing than after breeding, likely due to increased fecal deposition and favorable environmental conditions. Significant variations in parasite loads were observed across three previously identified erosion level zones of the colony, suggesting that microhabitat characteristics influence parasite persistence. This research highlights the effectiveness of non-invasive soil sampling in detecting parasite exposure over time and underscores the importance of continued monitoring of penguin health and parasite exposure, particularly in response to anthropogenic stressors. Future studies should integrate direct parasitological methods and molecular techniques to further understand host-parasite interactions.