Brook trout (salvelinus fontinalis) and lake trout (S. Namaycush) are the only charr native to the great lakes, and are culturally important species that support economically valuable fisheries and…

Brook trout (salvelinus fontinalis) and lake trout (S. Namaycush) are the only charr native to the great lakes, and are culturally important species that support economically valuable fisheries and are foundational to the ecological health of the region. However, since the early 1900S, genetic and phenotypic diversity of brook trout and lake trout in lake superior have declined, resulting in diminished gene pools in both species. Hatchery stocking has played an important role in rehabilitation efforts, but information on the genomic impacts of hatchery stocking on wild brook trout and lake trout is incomplete. In particular, stocking of splake, an anthropogenic hybrid of brook trout and lake trout, has occurred in lake superior since the 1970S. IT is not known whether splake introgress with brook trout and lake trout in the wild, but previous studies of genetic relationships and reproductive biology indicate the potential for interbreeding. Introgression is often overlooked as a threat to native fish but can significantly reduce the genetic health of species. If introgression of splake alleles into wild populations of brook trout and lake trout is occurring, understanding the resulting genomic and phenotypic impacts will be critical to supporting healthy populations of brook trout and lake trout. Here, we aim to examine potential effects of splake introgression on the health and recovery of brook trout and lake trout across the U.S. Portion of the lake superior basin. We will conduct restriction site associated DNA sequencing in wild caught brook trout and lake trout to determine whether splake introgression is occurring and, if so, identify geographic locations where introgression is occurring. Additionally, we will employ low coverage whole genome sequencing of known hatchery crosses to assess survivorship and examine the phenotypic effects of splake introgression in brook trout and lake trout, and to provide a reference for distinguishing introgression in wild individuals. Finally, we will leverage the genomic datasets produced here to address additional questions central to the conservation and management of brook trout and lake trout, including assessing the health of genetically distinct populations and inferring introgression from stocked conspecifics. Results from our proposed research will significantly improve recovery efforts for brook trout and lake trout by providing critical information on the impacts of splake stocking, a more comprehensive understanding of both brook trout and lake trout genetic health in lake superior, and identifying target areas for management intervention.