Visitors from Yellowstone are Making Themselves at Home

Eyed Lake Trout eggs incubating. Photo by Angela Baran-Dagendesh/USFWS.



The Genoa National Fish Hatchery (NFH) have some visitors that are making themselves right at home. In fact, they like southwest Wisconsin so much that they don’t plan to leave for at least 16-18 months. That is if all goes as planned and they clear their 3 fish health exams and are able to visit other exotic places such as the Iron River (WI) National Fish Hatchery and Sullivan’s Creek (MI) National Fish Hatchery. There they will be incorporated into the Fish and Wildlife Service’s long range effort of restoring lake trout to the upper Great Lakes. The reason why we are so interested in having these visitors from Wyoming come stay with us is that many decades ago, lake trout from Lake Michigan were stocked into Lewis Lake in Yellowstone National Park. These fish, even though stocked generations ago still should maintain a cadre of genetics that was developed over time to survive in Lake Michigan. This genetic refugia is doubly valuable, as nearly all of the native lake
trout in Lake Michigan disappeared due to the effects of pollution, overharvest and the introduction of the parasitic sea lamprey into the Great Lakes. The Service has developed this Lewis Lake strain into a captive broodstock and egg source in order to use in their re-stocking efforts. Biologists from Iron River NFH and the Jordan River (MI) NFH with the Lander (WY) Fish and Wildlife Conservation Office captured adults from Lewis Lake and collected eggs from 150 pairs of adults and shipped them to Genoa’s quarantine facility. The eggs are being carefully cared for and equal numbers from each egg take will be used to make 2 lots of broodstock. The lots will be housed in Genoa’s quarantine facility until they clear 3 separate fish health inspections. Then they will be transported to the Service’s captive broodstock stations and the 2 lots will then be crossed with one
another. This is to reduce any chance of interbreeding with other closely related fish. Careful managementshould preserve the genetic diversity of the brood line and also ensure a fighting chance of survival once the yearling fish are released. Great progress has been seen in Lake Huron and Lake Superior in developing self sustaining lake trout populations, and with this native strain of lake trout available for stocking in, it is hoped that we may someday see the same results in Lake Michigan.
By: Doug Aloisi