Recommendations for restoration of lake trout in Lake Michigan are increasingly being focused on re-establishment of the species at deep offshore reefs, since these areas historically sustained the greatest numbers of lake trout.

This focus is also based on the increasing impact of non-native fishes, such as alewife and round goby that prey on and compete with lake trout fry in shallow water.

Development of a successful strategy for re-establishing deep-water lake trout will require a better understanding of the challenges to a species that evolved in shallow water.  In a paper recently publish by the Journal of Great Lakes Research (www.jglr.org) on native species restoration, Charles Bronte (Green Bay Fish and Wildlife Conservation Office) working with researchers from the Universities of Vermont, Michigan, and Wisconsin, and the Michigan Department of Natural Resources, outlined the physical and biological challenges to such an effort.

The challenges include an annual temperature cycle that may impact reproductive timing and embryo incubation, no apparent physiological mechanism for filling the swim bladder, and no local prey supply for the newly hatched fry.

The team proposes that plans for restoration of lake trout into deepwater habitats in Lake Michigan must proceed in concert with research leading to a better understanding of extant deepwater strains in Lake Superior that have overcome these perceived limitations.