New data on gastrointestinal helminths in shags (Phalacrocorax verrucosus) at Kerguelen Archipelago

Abstract

To date, the knowledge of the helminth communities of Antarctic birds is scarce or fragmented. Knowledge about diseases and parasites is crucial for understanding and managing ecosystems, particularly in isolated areas where host species are more sensitive to new diseases or parasite infections. It has been showed that variations in rate of parasitism may occur between populations of host species. Two major non-exclusive hypotheses have been proposed to explain such variability: exposure to parasitism and, perhaps more important, life history strategies of hosts. We studied the helminth community of the Kerguelen Shag Phalacrocorax verrucosus, an endemic seabird species of the Kerguelen Archipelago. We provide new data on the helminths infecting this species from partial or complete digestive tracts of two birds. Two nematodes (Contracaecum rudolphii s.l. and Ingliseria cirrohamata) were found free or attached to the wall of the proventriculus of birds, while the acanthocephalan Corynosoma sp. and the cestode species Tetrabothrius sp. occurred in the intestine of the shags. The genus Tetrabothrius is reported for the first time in Kerguelen Shags and in this area. The analysis of stomach contents from 41 live Kerguelen Shag individuals revealed infection by Contracaecum nematodes. The proportion of infected birds differed between colonies, possibly in relation to differential exposure to infected fish hosts.