Rehabilitation of lake trout (Salvelinus namaycush), which historically was the coldwater apex predator of much of the Laurentian Great Lakes, is a priority for fishery management agencies in the region. In Lake Erie, the shallowest and southern-most Great Lake, successful rehabilitation of lake trout has been hindered by limited wild recruitment, possibly related to the lake's warm temperatures and restricted oxythermal habitat. I used acoustic telemetry tracking technology to investigate how lake trout spatial and thermal habitat use varies seasonally in Lake Erie to better understand whether limited recruitment could be caused by thermal conditions in the lake. As expected, lake trout were restricted to the offshore region of the eastern basin of Lake Erie during summer stratification. During fall, lake trout tended to occupy the southern nearshore region of the eastern basin, suggesting the importance of focusing spawning habitat restoration in this part of the lake. Tagged fish dispersed long distances at much higher frequencies than other Great Lakes populations of lake trout. Lake trout in Lake Erie occupied thermal habitat similar to other Great Lakes populations during summer stratification. Following destratification in fall, fish were exposed to warm temperatures, in some years for extended periods. Lake trout hatchery strains of Finger Lakes, NY, origin occupied similar summer temperatures and warm temperatures for more days during fall than Great Lakes origin strains, contrary to findings from Lakes Huron and Ontario. These results reveal behaviors that can inform management of lake trout in Lake Erie and throughout the Great Lakes and could begin to explain recruitment failure observed in Lake Erie.
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