Mass Fish Tagging Efforts Provide DNR with Critical Information

[Rick]

LANSING, MI - The Michigan Department of Natural Resources has been using the coded-wire tag program to mass mark various fish species in Michigan since the 1980s. This approach has provided critical data as fisheries biologists look to determine the value of naturally reproduced versus stocked fish.

The coded-wire tag program involves implanting a small, coded-wire tag, which is invisible to the naked eye, into the snout of a fish. A fish containing a coded-wire tag can be identified because its adipose fin (the small, fleshy fin between the dorsal and tail fins) has been removed. Anglers who catch these tagged fish then record valuable information, remove and freeze the fish’s snout, and drop it off at designated locations.

For many years, the DNR primarily tagged Chinook salmon and lake trout as part of its mass marking effort. Tagging these fish has helped biologists understand more about lake-wide natural reproduction and how many wild fish are available in the Great Lakes. It has also helped determine if the percentage of wild fish varies from year to year and how fish-stocking locations contribute to lake and river fisheries. Additionally, it provides insight into fish movement and where fish are stocked compared to where they are caught. Because of the value of the information the mass marking effort brings, the DNR, in conjunction with the U.S. Fish and Wildlife Service, has begun to coded-wire tag all Chinook salmon stocked into Lake Huron and Lake Michigan, as well as additional species including steelhead and Atlantic salmon.

“We rely heavily on Michigan’s anglers to return tagged fish and are appreciative of their cooperation,” said Dave Clapp, manager of Fisheries Division’s research section. “Participating in our mass marking effort allows us to learn more about the state’s fish species so we may manage them more effectively in the future.”

Because of the vast number of fish marked by this method (millions annually), there will no longer be rewards given to anglers for returning tagged fish. However, as in the past, any angler returning a coded-wire tagged fish to the DNR will still receive a letter describing the history of the fish caught (such as stocking location and age).

Since 1990, more than 25 million trout and salmon have been marked with coded-wire tags, and more than 100,000 tags have been recovered to provide information critical to the successful management of these fish populations.

To learn more about the DNR’s mass marking efforts, visit www.michigan.gov/taggedfish.