IDNR Report

Like many Hoosiers interested in their genetic ancestry, DNR fisheries biologists and Purdue University researchers are looking into the genetic makeup of a species of fish in northern Indiana's Lake Webster.

The results could have a bearing on how muskies, a popular sport fish, might affect the future of the DNR's muskie stocking program.

"We take eggs from adult muskies captured at Lake Webster in Kosciusko County each spring, fertilize and hatch them, and then grow the fry up to 10-inch fingerlings for stocking lakes throughout the state," said Randy Lang, DNR hatchery supervisor. "Without healthy brood stock, the entire muskie program could be in jeopardy."

That health, Lang said, depends in large part on the genetic makeup of Webster's muskies.

As a result of several recent changes in DNR egg-taking operations, fewer muskie eggs are now needed to supply the hatcheries. While that decreases the workload for crews that collect the eggs, it also increases the chances of inbreeding. By using an appropriate matchup of spawning fish, biologists hope to ensure a good genetic mix.

"Knowing more about the genetic condition of Webster's muskies will help us maintain long-term hatchery success," Lang said.

Webster Lake's muskie population was initially established in the 1980s from multiple sources throughout the Midwest, including Wisconsin and all other states between Iowa and Pennsylvania.

"That's a real hodge-podge of ancestry," Lang said.

Since then, muskies stocked into Lake Webster came from parent fish collected in the lake. That poses additional questions.

"Do we now have a unique population well-suited to Lake Webster but whose offspring may be less suitable for other lakes?" Lang said. "Or do we have a muskie population in Webster with a very narrow range of diversity that might eventually collapse?"

To examine the genetic diversity, a small section of fin has been clipped from each captured muskie and sent to Mark Christie at Purdue University. Christie has studied a variety of genetic issues related to wild and hatchery-produced fish populations.

"We're fortunate to have the tools of modern science and the knowledge of fish genetics right here in Indiana to help us make good decisions for Lake Webster muskies and help guide our program," Lang said.