Limited Spawning Habitat Poses Obstacles to Lake Trout Rehabilitation in Lake Erie

Attempts to reintroduce lake trout to Lake Erie have failed to establish a self-sustaining population in part due to limited knowledge of available high quality spawning habitat. With detailed information on substrate conditions at potential spawning sites, a better-informed management program may implement more precise stocking practices to bolster natural recruitment in this native, keystone species. We analyzed underwater video collected from 374 potential spawning sites in the eastern basin of Lake Erie, and determined the presence and abundance of substrate types at each site. Additionally, presence of underlying substrates, soft sediments, egg predators, dreissenid colonies, and indicators of wave energy were assessed. Sites were rated as either unable to support lake trout reproduction (poor), able to support reproduction with modification (moderate), or able to support reproduction in current condition (excellent) based on these criteria. We found that less than 1% of the potential spawning sites we sampled were of excellent quality, and that habitat degradation by dreissenids and fine sediments was wide spread. Our data suggest that low abundance of high quality spawning habitat may pose a substantial obstacle to the rehabilitation of lake trout in Lake Erie.