Minnesota has allowed anglers to keep too many big northerns over the years, tipping the biological balance in scores of lakes and leaving many teeming with small ''hammer-handle'' northerns that are hurting walleye and perch populations.
That's according to a retired Department of Natural Resources fisheries biologist, who predicts a dim future for quality walleye and northern fishing on hundreds of Minnesota lakes unless major fishing regulation changes are made.
"We need to do something drastic,'' said Jim Lilienthal, 67, of rural Brainerd, a member of Anglers for Habitat. "It will take restrictive regulations like we've never dreamed of to correct the situation.''
Such as allowing — and encouraging — anglers to take an unlimited number of northerns under 24 inches while allowing none over 24 inches to be kept. Would anglers keep and eat small northerns and release larger ones, in hopes of stabilizing the fisheries population?
"It will take a change in angler attitude,'' he acknowledged.
DNR fisheries chief Don Pereira doesn't dismiss Lilienthal's findings, but said "there's a lot of political and social stress'' involved in making major changes to fish regulations and management.
"We know large pike bring ecological stability to the system; they keep pike numbers under control,'' he said. "We've made some headway with special regulations. And we've tried to liberalize bag limits; it doesn't appear people want them [small northerns].''
But, he said, "We'll take a fresh look at it.''
'Annihilating perch population'
For decades, anglers have kept bigger northerns and tossed back small ones, hoping they will grow into trophies. Too often, Lilienthal said, that's not what happens. Instead, the removal of large northerns results in lakes with high densities of stunted northerns that consume small walleye, perch and sunfish — damaging the populations of all three species.
"We're annihilating the perch population, which in turn increases the vulnerability of juvenile walleyes,'' Lilienthal said.
An avid angler, Lilienthal examined DNR survey data on 1,000 lakes in central and northern Minnesota that are regularly stocked with walleyes. He looked at gillnet catches of northerns and walleyes. He found lakes in Otter Tail County with high densities of small northerns had half as many walleyes as lakes with more balanced northern populations.
"It clearly shows the statewide northern pike regulation is the cause of the high density small northern pike crisis on 374 of Minnesota's 722 stocked walleye basins in central and north-central Minnesota,'' Lilienthal said.
While Pereira acknowledges there is a growing northern pike problem, he said there's no evidence it's causing a widespread walleye problem.
"We're not brushing it under the carpet,'' he said. "We're taking what he is saying seriously.''
The statewide regulation allows anglers to keep up to three northerns, including one over 30 inches.
"That's totally unsustainable,'' Lilienthal says. The regulations allow too many big fish to be taken, he said, while preventing the needed removal of small northerns.
"One fish over 30 inches per year is more realistic than one over 30 inches per day,'' Lilienthal said. "We can't afford to lose those big fish.''
Lilienthal suggests dramatic changes are needed on problem lakes: Perhaps allowing unlimited harvest of northerns under 24 inches, while allowing none over 24 inches to be kept.
"We need something drastic to drive home that this is a huge problem,'' he said.
Without such changes, Lilienthal said, "I don't see any hope for anything but more smaller pike.''
Pereira said he sees the irony in the current regulations.
"Historically, they reduced the [northern] bag limit to three, and we have a six-fish walleye limit. It seems like the inverse would make more sense.''
But politically, such a change would be difficult, he said.
Legislature intervened
The DNR began working with angling groups more than 20 years ago to try to boost the average size of northerns in some lakes. Experimental regulations were introduced on some lakes in the early 2000s, and the agency adopted a long-range northern plan in 2008. The DNR limited the waters with special regulations to about 125.
Those special regulations, which usually involved a protected slot limit, usually succeeded in increasing the number of larger northerns.
But while many lake associations and anglers pushed for the special rules, other anglers and spearers objected to restricting their ability to take northerns.
Leaders of the Minnesota Darkhouse and Angling Association went to the Legislature in 2011 and succeeded in getting the number of lakes with special northern regulations capped at 100, forcing the DNR to remove regulations from about 19 lakes, and preventing the agency from adding any more lakes.
Lilienthal said his research clearly shows lakes with high densities of northerns have lower densities of walleyes, and he bluntly says the Legislature's 2011 law was "a stab in the back for modern northern pike management.''
Pereira said the law has handcuffed the DNR, preventing the agency from dropping special northern regulations on lakes where they don't appear to be working, and preventing them from adding regulations to lakes where they might work.
Meanwhile, Vern Wagner, vice president of Anglers for Habitat, said his group plans to take the issue to the Legislature this year.
"We just feel this is something Minnesota anglers need to know about. It's impacting our walleye-stocking efforts.''
Doug Smith • doug.smith@startribune.com
Twitter: @dougsmithstrib
