Data from: Invasion of the Hawaiian Islands by a parasite infecting imperiled stream fishes

Points of origin and pathways of spread are often poorly understood for
introduced parasites that drive disease emergence in imperiled native
species. Co-introduction of parasites with non-native hosts is of
particular concern in remote areas like the Hawaiian Islands, where the
introduced nematode Camallanus cotti has become the most prevalent
parasite of at-risk native stream fishes. In this study, we evaluated the
prevailing hypothesis that C. cotti entered the Hawaiian Islands with
poeciliid fishes from the Americas, and spread by translocation of
poeciliid hosts across the archipelago for mosquito control. We also
considered the alternative hypothesis of multiple independent
co-introductions with host fishes originating from Asia. We inferred
conduits of introduction and spread of C. cotti across the archipelago
from geographic patterns of mtDNA sequence variation and allelic variation
across 11 newly developed microsatellite markers. The distribution of
haplotypes suggests that C. cotti spread across the archipelago following
an initial introduction on O'ahu. Approximate Bayesian Computation
modeling and allelic variation also indicate that O'ahu is the most
likely location of introduction, from which C. cotti dispersed to Maui
followed by spread to the other islands in the archipelago. Evidence of
significant genetic structure across islands indicates that contemporary
dispersal is limited. Our findings parallel historical records of
non-native poeciliid introductions and suggest that remediating invasion
hotspots could reduce the risk of infection in native stream fishes, which
illustrates how inferences on parasite co-introductions can improve
conservation efforts by guiding responses to emerging infectious disease
in species of concern.