Invasive species such as lamprey eels and zebra mussels have impacted native species in the Great Lakes, but recent observations show that lake trout may be making a strong and steady comeback.

From Fox 11:

“Dale Hanson is looking for what he calls the perfect lake trout. The fisheries biologist with the U.S. Fish and Wildlife Service is conducting a survey in Lake Michigan. Nearly a mile of nylon netting is set about two miles off the Sheboygan shore…

Hanson says lamprey eels, zebra mussels and little fish called alewives have hurt the lake trout. Hanson says salmon have gobbled up many of the alewives, and the lake trout have started to reproduce on their own. 
‘Right now, in areas of the lake, we’re seeing roughly 20 percent of the fish are unclipped, but that is by no means observed on a lake-wide basis,’ said Hanson.”
While not definitive, the indications are good that lake trout have begun reproducing in the wild. Read the complete article at the link above.