Data from: Genomics and telemetry suggest a role for migration harshness in determining overwintering habitat choice, but not gene flow, in anadromous Arctic Char

Migration is a ubiquitous life history trait with profound evolutionary
and ecological consequences. Recent developments in telemetry and
genomics, when combined, can bring significant insights on the migratory
ecology of non-model organisms in the wild. Here, we used this integrative
approach to document dispersal, gene flow and potential for local
adaptation in anadromous Arctic Char from six rivers in the Canadian
Arctic. Acoustic telemetry data from 124 tracked individuals indicated
asymmetric dispersal, with a large proportion of fish (72%) tagged in
three different rivers migrating up the same short river in the fall.
Population genomics data from 6,136 SNP markers revealed weak, albeit
significant, population differentiation (average pairwise FST = 0.011) and
asymmetric dispersal was also revealed by population assignments.
Approximate Bayesian Computation simulations suggested the presence of
asymmetric gene flow, although in the opposite direction to that observed
from the telemetry data, suggesting that dispersal does not necessarily
lead to gene flow. These observations suggested that Arctic Char home to
their natal river to spawn, but may overwinter in rivers with the shortest
migratory route to minimize the costs of migration in non-breeding years.
Genome scans and genetic-environment associations identified 90 outlier
markers putatively under selection, 23 of which were in or near a gene. Of
these, at least four were involved in muscle and cardiac function,
consistent with the hypothesis that migratory harshness could drive local
adaptation. Our study illustrates the power of integrating genomics and
telemetry to study migrations in non-model organisms in logistically
challenging environments such as the Arctic.