Genetics of Behavioural Diversity in Lake Superior Brook Trout

We tested for genetic variation in behavioral traits believed to be tied to migratory behavior using crosses between migrant and stream resident Brook Trout (Salvelius fontinalis) caught from tributaries along the north shore of Lake Superior. Two ecotypes of Brook Trout occur in Lake Superior: a large-bodied ecotype that migrates to lake and a small-bodied ecotype that remains stream resident. The abundance and distribution of the migrant ecotype has declined and is the focus of conservation concern. In 2011, migrant and non-migrant adult Brook Trout were captured in the field and crossed to create 26 families. In 2012 and 2013, respectively, ten offspring from each family were assessed experimentally for risk taking, general activity, sociability, and propensity to disperse. At both developmental time points (0+ and 1+), individuals differed repeatedly in behavior. Offspring behavior varied among families but was not related to the migratory behavior of parents. These results suggest that there may be a heritable component to the behavioral variation. This research will assist managers with efforts to conserve and restore these populations, by helping understand whether the observed life history variation in Lake Superior Brook Trout populations is due to a genetic polymorphism or phenotypic plasticity.