Cooperative Fish and Wildlife Research Units Program: Pennsylvania
Education, Research and Technical Assistance for Managing Our Natural Resources

Lake trout were extirpated from Lake Ontario in the late 19th century, and since the early 1970s stocking efforts have been attempting to re-establish a naturally reproducing population. Restoration efforts face many challenges including high mortality rates of yearlings during the first few days of stocking, reduced egg survival due to Early Mortality Syndrome (EMS) and predation by non-native fishes, and degraded spawning habitats due to sedimentation and introduced dreissenid mussels, among others. Lake Ontario is currently stocked with two hatchery strains: Seneca strain and the Traverse Island/Lake Superior strain (Lantry and Lantry 2008), but low numbers of wild lake trout also exist in the basin. Although some lake trout are naturally reproducing in the lake and Niagara River, there are still uncertainties related to strain-specific contributions to natural reproduction and the timing and location of spawning within the river. This study aims to genetically characterize the lake trout hatchery strains which could contribute to natural reproduction in Lake Ontario, and to evaluate the contribution of these strains to reproduction being documented in the Niagara River. Based on the genetic differences between hatchery strains, and incorporating any wild lake trout sampled from near the spawning area, assessment of the source(s) of lake trout natural reproduction in the Niagara River area will be assessed. If hatchery lake trout are reproducing successfully in the Niagara River, evaluation of the particular strain can be used to inform stocking practices or strain selections necessary to increase natural reproduction in Lake Ontario. In addition, lake trout will be tagged with radio transmitters and tracked to assess lake trout movement, with focus on strain-specific reproductive patterns and behaviors.