On the distribution and abundance of eel parasites in Nova Scotia: local versus regional patterns

Site-to-site variation in macroparasite species distribution and richness was observed in eels (Anguilla rostrata) among 7 sites in the Timber Lake drainage system, Nova Scotia. There was a positive relationship between maximum local species distribution, as measured by maximum prevalence at a site, and regional distribution, as measured by the number of sites in which a parasite was found within the watershed and among 28 sites across Nova Scotia. Species richness increased with spatial scale. However, the species richness of host-specific parasites approached a maximum at the spatial scale of the watershed, whereas that of generalist parasites continued to increase with increasing scale. The near-peak in species richness of eel specialists at the watershed level suggests that in a functional sense for these parasites it is the spatial scale of the watershed that serves as a species pool from which local species richness is derived.