Potential Habitat Limitations to Lake Trout Restoration in Lake Erie

Following the extirpation of native lake trout from Lake Erie, efforts to rehabilitate the species have involved judicious stocking together with suppression of the parasitic sea lamprey; the assumption being that mortality from lamprey was the main factor limiting rehabilitation.  Until recently much of the stocking was targeted at areas associated with an historic spawning shoal.  Considerations for expanded stocking included the assumption that stocking should occur at potential spawning locations, designated based on similarity to historic spawning shoal habitat.  Traditional descriptors of spawning habitat include substrate, slope, depth, and proximity to nursery habitat.  We describe habitat investigations of historic and potential spawning shoals in Lake Erie using Sidescan sonar and underwater video.  Further, we consider recapture locations of stocked lake trout relative to stocking locations and investigated habitat. We describe alterations to habitat caused by dreissenid mussels, attached filamentous algae and sedimentation, and the potential of non-traditional spawning habitat for use by stocked lake trout.  While its historic role as a native species remains relevant to the ecosystem, the habitat to which this species was adapted has changed.  The success or failure of rehabilitation may depend upon the ability of stocked lake trout to utilize non-traditional spawning habitat.