Apologizing for a “deeply discouraging” walleye fishing conundrum on Lake Mille Lacs, the head of Minnesota’s Department of Natural Resources on Friday extended by two weeks a midsummer ban on walleye fishing to keep too many fish from being killed.

“This is profoundly difficult,” said Commissioner Tom Landwehr. “This is what we have to do to help this fishery recover in a reasonable time.”

A three-week shutdown on walleye fishing on the lake that was supposed to end July 27 now will run until Friday, Aug. 11. When walleye fishing reopens, catch-and-release angling will be allowed through Labor Day, Sept. 4.

Landwehr acknowledged that a longer shutdown will add to economic and cultural strains felt by Mille Lacs area resorts, anglers and the community at large. Two weeks ago, protesters in boats circled Gov. Mark Dayton as he fished for bass on Mille Lacs to promote it as a multispecies fishery. The demonstrators were angry about three consecutive years of heavy walleye restrictions that have shackled the pursuit of a once-bountiful resource.

“The DNR has lost its credibility up here,” local resort owner Terry McQuoid said Friday. “This whole thing is damaging for our area.”

He and other Mille Lacs area residents don’t agree with the DNR’s position that the lake’s walleye population is critically undersized. Their disbelief stems from historically high walleye catch rates that the DNR says are linked to a shortage of forage in the lake, not an abundance of walleyes. The DNR also has said that the hot bite also is the result of catchability increasing when the fish population drops.

McQuoid scoffs at that. “You can’t have a lake in crisis when you are catching fish like we have been catching them,” he said. “If we believed the walleye population was in trouble, we’d be the first to say, ‘Let’s shut it down.’ ”

But state and tribal fisheries managers say scientific measurements of the walleye population show a significant, ongoing decline in young walleye numbers. A group of eight Chippewa bands co-manages the lake along with the DNR; scientists on both sides agree every year to a safe harvest level.

This year the DNR and Chippewa bands agreed to harvest quotas of 44,800 pounds for state anglers and 19,200 pounds for tribal fishing. State fisheries chief Don Pereira said Friday that the state already has exceeded its baseline quota. Minnesota will dip into an optional reserve quota of 11,000 pounds to reopen the season Aug. 11, a decision that will put the state deeper into arrears on a walleye ledger that must be paid back over the next three years.

“We want to allow as much walleye fishing on Mille Lacs as possible,” Pereira said. “So even though state anglers already have caught their quota of fish, the DNR will dip into the allowed conservation overage to reopen the season on Aug. 11.”

Dylan Jennings, a spokesman for the Great Lakes Indian Fish & Wildlife Commission, said Friday that the Chippewa bands are pleased that the state is keeping to its agreement on walleye quotas and paybacks. “We stand by the state,” Jennings said. “It’s to protect the resource.”

Pereira said the state caused tribal officials “considerable displeasure” last year by “pushing the envelope” and exceeding the state’s 2016 Mille Lacs walleye quota by 6,800 pounds. To resolve the conflict, the state must pay back the overage — including the extra 11,000 pounds expected to be taken next month — in equal parts over the next three years.

That means Minnesota’s annual walleye allotment will be reduced by about 6,000 pounds in 2018, 2019 and 2020. The allotments are set each year in late fall based on annual population surveys conducted via sampling with nets.

Landwehr said the DNR’s goal is to return the Mille Lacs walleye fishery to a “more prosperous situation.”

The agency continues to study why baby walleyes in the lake are not surviving in steadfast numbers. Part of the problem, scientists have said, rests with zebra mussels and spiny waterfleas. Those two invasive species are consuming great amounts of nutrients previously available to native fish and other organisms in the lake’s food web.