Difficult as it has been for Lake Mille Lacs walleye anglers to find a fish to fry, it might be doubly so this summer.

Worried about a declining walleye population in the state's premier fishing lake, state and Chippewa officials have cut in half the number of walleyes that can be taken from the lake starting in May.

The decision means regulations likely to be imposed by the Department of Natural Resources could keep anglers from going home with any walleye filets.

"It sounds horrible," said Eddy Lyback, who owns Mille Lacs marine and ice fishing businesses.

But DNR officials said the decline in the walleye population is so complex and involves so many variables -- including increases in smallmouth bass and northern pike, a zebra mussel invasion, a warming climate and the effects of fishing regulations and tribal fishing -- that they have few options.

"We want to be very cautious," said Tom Jones, DNR large lake specialist. "We are definitely in a spot we've never been before."

The numbers tell the story:

• The combined walleye harvest for sport and tribal anglers is being sliced from 500,000 pounds in 2012 to 250,000 pounds this year. That's the lowest "safe harvest" quota since the state and Chippewa bands established them in 1997.

• Anglers' share will be 178,750 pounds, and band members will get 71,250 pounds -- both half the 2012 quotas.

• Last year, anglers harvested about 310,000 pounds of walleyes, which includes 136,000 pounds that died from hooking mortality but is included in the state's allotment. The bands took 80,000 pounds, nearly all by spring netting.

'A big mess'

The quota reduction for the state's share is the largest ever, and it's the first time the bands ever have reduced their quota.

"The people who will suffer the most will be businesses around the lake, like they always have," Lyback said. "It's a big mess the state has gotten this lake into, and they'd better figure out a way to straighten it out."

The bands haven't determined how they'll respond to the lower quota, said Sue Erickson, public information officer for the Great Lakes Indian Fish and Wildlife Commission, which represents 11 Chippewa tribes in Minnesota, Wisconsin and Michigan.

"The tribes are very concerned for the long-term health and sustainability of the lake," she said. "The mortality has to be reduced from all sources."

DNR officials said they expect the bands again will use gill nets in the spring, when walleyes are in shallow water spawning. The nets tend to target smaller male walleyes, whose population decline the DNR is particularly concerned about.

A disturbing trend

Based on DNR surveys, walleyes in the 200-square-mile lake have fallen to their lowest level in 40 years.

While DNR and tribal biologists still are assessing the situation, officials say the disturbing trend likely has been caused by a combination of factors, possibly including the unforeseen result of fishing regulations that directed anglers' harvest to the lake's smaller walleyes.

"We've had some of the best and brightest fisheries researchers [in the nation] look at this," said Don Pereira, DNR fisheries research manager. "Perhaps we should have been spreading the harvest out over a broader array of size and age range of walleyes.

"Did we do too good a job of protecting larger walleyes?"

Added Jones: "We're considering trying to reduce northern pike and bass densities by allowing more harvest."

Currently, smallmouth bass less than 21 inches must be released, and the possession limit is one. Northerns between 27 and 40 inches must be released, and the possession is three, with one allowed over 40 inches. No spearing is allowed in the winter.

A hard time

DNR officials still are working on fishing regulations that will become effective in May and will meet next month with the Mille Lacs Lake Input Group, a consortium of resort owners, bait shops and other businesses.

Fishing has been good on the lake in recent months, but because of the shortage of small walleyes, anglers have had a hard time catching fish to keep.

Current regulations require walleyes from 17 to 28 inches to be released, with one fish over 28 inches allowed in the four-fish bag limit.

"It's been pretty much a catch-and-release fishery all winter," Lyback said.

A 1999 U.S. Supreme Court decision affirmed off-reservation hunting and fishing rights held by the eight Chippewa bands and established the "co-management" of Mille Lacs between the state and bands.

Staff writer Dennis Anderson contributed to this report.