NEAR WALKER, MINN. – Call it a Minnesota angler's Dream Lake — a body of water with lots of voracious fish, some of which have been caught, measured and weighed as many as 20 times before being returned to the frigid depths below.

Perhaps someday all Minnesota lakes will be managed similarly.

"Wouldn't it be nice,'' said Dallas Hudson, "if everyone could fish lakes where the fish aren't stunted or haven't been killed off by people keeping too many?''

One of four landowners on a 160-acre private lake that he and others are researching, Hudson spoke on a recent day while a half-dozen of us stood over 2 feet of hard water. Every 20 minutes or so, someone set the hook on a northern pike, hoping to hand-line it through a watery cylinder Hudson had bored into the ice.

For about 20 years, Hudson and lifelong fishing pal Steve Bayman, both of Akeley, Minn., and both 49, have forsworn keeping northern pike from this lake. They also release most crappies and bluegills, withholding only the smaller specimens for an occasional meal.

The reason: They got sick of catching hammer-handle-size northerns, puny crappies and miniature bluegills — the result, they say, of too many people, themselves included, catching and keeping too many fish, particularly big fish.

The Minnesota Department of Natural Resources has joined Hudson and Bayman on their excellent fishing adventure, and it allows them to implant identification tags in fish they catch and release in the lake.

"Dallas' work shows us pretty clearly how vulnerable northerns, in particular, are to being caught,'' said DNR area fisheries supervisor Doug Kingsley of Park Rapids, Minn. "When you can catch the same fish 15 times over, and sometimes two times in the same day, it seems clear that in many lakes we need to limit the harvest of larger fish if we want bigger northern pike in our lakes.''

For Hudson and Bayman, the conversion from fish keepers to fish researchers-cum-release artists was a long time coming. And perhaps somewhat surprising, given their northern Minnesota street cred as pickup-driving, Carhartt-wearing, gun-toting hunters, trappers and fishermen.

"As a kid after school in winter, I'd walk onto 11th Crow Wing Lake to catch — and keep — a lot of walleyes,'' Hudson said. "And spear northerns. I killed a lot of northerns.''

But finally, desperation set in. That's because 11th Crow Wing is no longer the angling mecca it once was, and neither, Hudson said, are other lakes in the Akeley and Walker area.

More specifically to his fishing interests, no longer did the lake he lives on boast bragging-size northerns. Or, for that matter, plump bluegills. Or slab crappies.

"Too many people keeping too many fish,'' he said. "It's that way in most Minnesota lakes.''

So along with Bayman, Hudson struck a deal with his fellow lakeshore owners. There would be no spearing. No keeping northerns caught by hook and line. And no getting greedy with big panfish — bluegills particularly.

"I've always been curious how things in nature work,'' said Hudson, a hydrotechnician with the U.S. Geological Survey. "What kind of plant is that? What kind of animal is that?''

Now he asked himself: Is it possible to once again have larger fish in his lake? Walleyes, he knew, were out of the question without stocking, because they had been fished out decades ago.

Nor would there be a comeback for muskies, a fish that was native to his lake but that also had been eradicated by fishing pressure.

But what about northerns, bluegills and crappies — the lake's bread and butter fish? Were they forever destined to be stunted representations of their former selves?

Or could the lake — whose water quality and vegetation benefit from limited shoreline development — be returned to its more natural state, with fish across a broad spectrum of age and size structures, including older, bigger fish?

These many years later, the answer seems to be "yes." And not just for northerns but for bluegills and crappies, too.

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Consider:

Of the 97 northern pike caught this winter from Hudson's study lake, only seven hadn't been caught previously. In fact, as a group, the 97 fish had been caught and released a total of 431 times.

And of those 97, a total of 24 measured 30 inches or longer — fish that had been caught over the course of their lives an average of 6.83 times apiece.

"Now think about how long it takes a fish to grow,'' Hudson said. "A northern in our lake will take six years to reach 24 inches and nine years to reach 30 inches and weigh 7 or 8 pounds.

"So it becomes pretty obvious what happens if people keep not only the bigger fish, but the medium-sized fish, say 24- to 30-inch northerns. You end up with what we have in many Minnesota lakes: stunted fish.''

Just then, another tip-up flag stood upright, and two of Hudson's volunteer anglers for the day, Sam Hunter of Nevis, Minn., and Megan Malone of Menahga, Minn., raced in its direction.

Hunter is a DNR conservation officer and Malone an emergency medical technician. Both were enjoying some off-duty time helping Bayman and Hudson catch, measure, weigh and tag northern pike.

"Got it!'' Malone said as she set the hook on yet another toothy fish.

This northern, once winched into the bright sunlight, proved small — and a rarity: It bore no tag; therefore, it hadn't been caught before.

With a surgeon's alacrity, Hudson quickly measured the fish, attached an ID tag to it and removed a scale from its side to determine its growth rate and age.

Then the fish was returned to the water, likely to be caught again. And again. And again.

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Kingsley, the DNR fisheries manager, believes Hudson's and Bayman's research, along with similar studies, shows that the often-referenced Minnesota goal of returning bigger northern pike to state lakes is unlikely to occur, given current harvest regulations that allow anglers three northerns daily, with one over 30 inches.

"Depending on an individual lake and the fishing pressure it sustains, it's possible its northern pike population can't even sustain a regulation allowing anglers one fish greater than 24 inches a day,'' he said.

Conversely, smaller "hammer-handle'' northerns likely can be harvested from most lakes in quantities greater than three a day, if anglers could be convinced to do it.

Complicating the DNR's fish management options is a law passed by the Legislature in 2011 at the behest of spearing proponents that limits the establishment of length-based fish harvest regulations to 100 lakes in the state.

"I don't have all the answers,'' Hudson said. "But it's pretty obvious we've been taking too many large fish from our lakes. Which might also explain why many of our lakes have so many small fish, northerns in particular, because a larger population of big fish could reduce the population of small fish.

"Someday, I'd like to see the DNR allow everyone to tag fish. Then when they catch fish and see they're tagged, they'd understand the fish have been caught before and that maybe the fish should be released so they can be caught again.''

Dennis Anderson • danderson@startribune.com