Geographic variation in composition of metazoan parasite infracommunities in Galaxias maculatus Jenyns 1842 (Osmeriformes: Galaxiidae) in southern Chile (38-47° S)

Abstract

Galaxias maculatus is an abundant freshwater fish species in Chilean continental waters where it plays important ecological functions, yet few parasitological records of this species exist in Chile and all of them cover a very limited geographic range. The objective of this study was to assess large scale geographic variation in composition of parasite infracommunities of Galaxias maculatus. Specifically, parasite infracommunities of this species were compared among 11 locations across 9 degrees of latitude and 3 ecosystem types (lake, river and estuary). Most taxa found had been previously reported in Chile and Argentina. However, this is the first report for Tylodelphys sp. in this host in Chile. Furthermore, the cranial parasite Tylodelphys sp. had the highest overall prevalence and abundance compared to other parasite species. Despite the fact that the abundance of Tylodelphys sp. was not significantly correlated with Fulton’s condition factor of fish, infected fish seem to have a better body condition compared to uninfected ones. The most important source of variation in composition of infracommunities was the sampling location. Furthermore, fish from lakes have a different composition of parasite infracommunities mainly due to higher abundances of Tylodelphys sp.