Gastrointestinal helminths of two storm-petrel species, Oceanites oceanicus and Fregetta tropica, (Aves: Oceanitidae) from Antarctica

Although knowledge about parasitic diseases in Antarctic birds is scarce, an increasing number of studies is currently being carried out in this area. A better knowledge of host-parasite relationships in Antarctic seabirds is key to understanding trophic ecology and epidemiology of infection diseases, especially in those birds with extensive migratory routes that can act as reservoirs and distributors of diseases. This study aims to provide information on helminths of two storm-petrel species, the Wilson’s Storm-Petrel Oceanites oceanicus and the Black-bellied Storm-Petrel Fregetta tropica (Oceanitidae). Twenty freshly dead individuals were analysed: 18 O. oceanicus (8 adults, 10 chicks) and 2 F. tropica (adults). Fifteen O. oceanicus were parasitized with the nematode Stegophorus macronectes , whereas the two F. tropica were parasitized by at least one of three parasite species identified: S. macronectes , Seuratia sp., and Tetrabothrius sp. The low richness of parasites may be associated with a stenophagic diet. However, a clear difference is observed between both host species that could be related to a higher fish ingestion by F. tropica , unlike O. oceanicus with a higher ingestion of krill.