Michigan DNR to track fish stocking using 23andMe-style gene testing

The Michigan Department of Natural Resources has begun using genetic testing to track the success of some of its fish-stocking operations. The goal is to find out if fish living in a particular water body descended from the parents of stocked fish. Doing so helps the DNR know if its multimillion-dollar stocking efforts are paying off by telling them if the stocked fish are living on in the waterway.

“Think about genetics (testing) like Ancestry.com, 23andMe,” Jen Johnson, senior fisheries management biologist for the DNR, told the Michigan Natural Resources Commission during its meeting Wednesday in Marquette. That’s the big question that we’re asking here.” The DNR spends about a third of its annual budget on fish rearing and stocking. In the 2024-25 fiscal year, that totaled over $11 million.

According to the department, past methods of tracking success have been limited or costly. Pilot research with the new method, known as parentage-based tracking, has been cost-effective, freed up staff time, and has shown some illuminating results. “This tool is going to open up a lot of insights into what we do at the fish division,” said Randy Claramunt, fisheries chief for the DNR.

It will allow the division to assess whether fish they catch were born naturally or from fish bred and stocked by the DNR, which will give them a sense of which approach is working better. The DNR breeds and stocks fish primarily to create new places for people to fish a certain species or to add numbers to struggling populations. The department can check to see if stocked fish are surviving in their introduced location by tagging the fish and then searching for them there at a later date.

But tagging methods have been problematic. Using physical tags has meant individually tagging fish. Tags can get lost or an angler may fail to report when they reel in a tagged fish.

Another method of tagging involves internally marking fish, but that method can only be verified on dead fish using a microscope, and it takes up a lot of staff time. It’s also more expensive than genetic testing. Parentage-based tagging involves genetically analyzing the DNA of the parents of a brood of stocked fish.