NDGF tagged walleye
By Doug Leier
If you’ve ever caught a tagged walleye, you might have wondered what story that fish could tell. Where has it been? Where was tagged? How long did it live? You’re not alone. The interest and curiosity are shared by anglers and biologists alike. It’s fascinating to think of the life cycle, biology and fisheries behavior going on beneath the water.
For fisheries biologists, those little tags are of huge importance.
One of the primary reasons the North Dakota Game and Fish Department conducts fish-tagging studies is to estimate exploitation — the percentage of fish anglers harvest from a population each year. Knowing how many fish are being kept helps fisheries managers determine whether current regulations are sustainable and whether anglers will continue to enjoy strong fishing opportunities in the years ahead.
Tagging studies reveal far more than just harvest rates, however. Each returned tag adds another piece to the fisheries puzzle.
Biologists learn when fish are harvested during the year, whether anglers release certain sizes more often than others, how often fish spawn, and whether they return to the same spawning sites year after year. Tagging also reveals one of the most interesting aspects of fish biology: movement.
Fish move for many of the same reasons people do. They’re searching for food, the right temperatures and simply avoiding predators. Over time, biologists learn travel patterns for each species.
Take paddlefish, for example. Their torpedo-shaped bodies and powerful forked tails make them built for distance. In Lake Sakakawea, paddlefish roam the reservoir feeding on tiny zooplankton. When it’s time to spawn, mature fish often begin an upstream journey that can stretch hundreds of miles into the Yellowstone River.
Walleyes, on the other hand, are typically more like homebodies. Their body design favors short bursts of speed rather than marathon swims. That’s also why they produce the white, flaky fillets that anglers prize. If you want a comparison outside the water, think of long-distance fliers like snow geese versus birds that prefer staying closer to home, like pheasants.
Still, every species has its outliers.
A good example came from Lake Oahe. In April 2020, fisheries crews tagged an 18-pound female northern pike in Beaver Bay. Nearly a year later an angler caught and harvested the fish in Whitlock Bay in South Dakota — a journey of 102 miles and the longest documented movement for a pike tagged in North Dakota.
Tagging studies also highlight the remarkable longevity of some fish.
One paddlefish netted on the Yellowstone River in 2007 was transported to Garrison Dam National Fish Hatchery and used as brood stock to produce young paddlefish for stocking. After spawning, the 87-pound fish was tagged and released back into Lake Sakakawea. Eighteen years later, during the 2025 paddlefish snagging season upstream of Williston, an angler caught and harvested that same fish. It weighed 98 pounds.
Decades of tagging on Lake Sakakawea have confirmed what many anglers suspected — most walleyes don’t wander far. Biologists divide the lake into three regions: upper, middle and lower. Most tagged walleyes are recaptured in the same region where they were originally tagged, with fish in the lower end of the reservoir being the most faithful to their home waters.
But there are always a few exceptions.
One walleye tagged in 1995 at White Earth Bay was recaptured by Game and Fish crews at the exact same spawning location multiple times over the next decade. It returned in 1998, 1999, 2003, 2005 and 2006, showing remarkable loyalty to that spawning site before eventually being kept by an angler downstream in 2007.
Another fish tagged in 1997 near Parshall Bay avoided anglers and sampling nets for nearly three decades before finally being caught and harvested in 2025 — 28 years after it was first tagged.
Perhaps the most surprising traveler was a walleye tagged in 2021 at White Earth Bay. Two years later an angler reported catching and releasing it below Fort Peck Dam in Montana — 277 river miles upstream from where it started.
Stories like these are fascinating for biologists and anglers alike, but they also highlight something important. Every tag returned by an angler helps fisheries managers better understand the fishery and make informed decisions.
So, if you happen to catch a tagged fish this season, take a moment to report it here on the Game and Fish website https://gf.nd.gov/fishing/report-a-tagged-fish. Thank you in advance.
Your report helps fisheries biologists and managers make decisions for the future, and you never know the story it could create.
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