Researchers have discovered a very special population of fish lurking in the depths of Elk Lake in Antrim County. These fish share a unique heritage, linking them to the native lake trout that disappeared from Lake Michigan over 50 years ago.
Killed by sea lamprey invading from the Atlantic Ocean and caught in too-many fishing nets, the native populations of lake trout were wiped out of Lake Michigan by the late 1950s. Only small, remnant populations carried on in Lake Superior and distant corners of the Great Lakes.
State fisheries biologist, Jory Jonas says, “Lake Michigan does not have any remnant forms. And, at this time, every fish that you collect, except for a few, are from stocking, primarily from the U.S. Fish and Wildlife Service.”
Jonas points out that researchers have believed that there were no native lake trout left anywhere in the Lake Michigan basin. So, she had quite a surprise while riding along with an inland lake survey.
“Yeah, I was out on a survey that I wasn’t even supposed to be on with an inland lake crew,” she said. “And they set this large trap net and they caught two lake trout and I happened to be on-board when they caught them. And I started asking questions. They looked like something different, and I wanted to know why they were there and who they were.”
Since the mid-1960s, the U.S. Fish and Wildlife Service has worked with other state and federal agencies, Indian tribes, and academic institutions to re-build a self-sustaining population of lake trout in Lake Michigan. Using a system of hatcheries, they raise fish from eggs and brood stock taken from distant places like Lake Superior and even the Finger Lakes of New York. Each of these strains of lake trout look and behave a bit differently from each other.
Research completed by Jonas and her colleagues shows that the Elk Lake trout is genetically distinct from the fish currently being stocked in Lake Michigan, and it looks different too. This fish is more torpedo shaped than the others, with slightly different fin characteristics.
Recent research conducted by CMU graduate student, Kyle Broadway indicates that the Elk Lake strain also behaves differently than the other stocked trout.
“The Elk Lake fish,” Broadway says, “tended to occupy much lower temperatures than what Great Lakes or Finger Lakes-origin lake trout were shown to occupy.”
Broadway, Jonas and other researchers hope that the Elk Lake strain of lake trout might help to restore self-sustaining populations in Lake Michigan someday. If this fish can be raised in hatcheries and re-introduced, the Elk Lake strain might occupy colder, deeper water than other predator fish, like salmon and other lake trout. At those depths, it might also avoid commercial fishing nets.
Jonas says restoration of naturally reproducing lake trout would be a big success for fisheries biologists. The restoration of lost genetic diversity Jonas says, “would also be extremely valuable, and create a more resilient population to handle future changes that might be down the line.”
Over the last few years, researchers have been finding more and more wild fish, as opposed to hatchery-raised fish. That suggests that the lake is changing in ways that are helping this native predator reproduce in the wild.
So, maybe this is a good time to re-introduce one of Lake Michigan’s original strains of lake trout hidden for so many years in Elk Lake.
Joe VanderMeulen publishes the web magazine Nature Change.