The biggest piece of ice fishing trash ever handled by Mille Lacs area game warden Scott Fitzgerald was a living room couch. But every winter there’s a new surprise and Minnesota ice anglers continue to scatter tons of garbage on frozen lakes across the state.

“It seems to be getting worse,’’ said Lt. Col. Greg Salo, enforcement division assistant director at the Minnesota Department of Natural Resources (DNR).

Salo said the biggest problem areas tend to be on lakes that attract large clusters of 100 or more independently operated fish houses. It’s normal for the occupants of those shacks or mobile wheelhouses to set refuse outside on the ice.

But some of those anglers never intend to pack it out while others give up quickly if the junk becomes attached to the ice or scattered by the wind.

“It’s not a violation until you leave it behind,’’ Salo said. “That leaves us with a small window to catch anyone.’’

Fitzgerald and Salo said the vast majority of resort owners who rent fish houses on Minnesota lakes are conscientious about garbage removal. Some, but not all, provide portable toilets. Any cleanup crew will tell you that discarded fecal waste is not uncommon.

“You’d be absolutely mortified by what people leave out there,’’ Fitzgerald said.

Ice fishing litter on the American side of Lake of the Woods got to be such a problem from Warroad to Baudette that a host of South Shore municipalities, civic groups, resorts and conservation agencies banded together in 2012 to form the Keep it Clean Committee.

Mike Hirst is a resource technician for Lake of the Woods Soil & Water Conservation District in Baudette who chairs the committee. In the past five years of campaigning for ice anglers to pick up after themselves, the committee has collected an estimated 500 tons of waste in seven strategically placed dumpsters. The committee’s annual $10,000 budget primarily goes to garbage haulers who keep the containers from overflowing.

DNR conservation officer Nicholas Prachar of Baudette, also on the Keep it Clean Committee, said the anti-litter campaign is helping because volunteers who clean up 15 miles of shoreline each spring are finding less trash than in previous years.

But Prachar still is frustrated by the carelessness and malice of some anglers. Operators of expensive wheelhouses who visit the lake for overnight stays have become the worst violators, he said.

“If you can dream of it, it’s been left out there on the ice,’’ Prachar said. “It’s such an issue, and it’s just going to pollute the lake.’’

Empty beer cans, discarded food, cardboard boxes, fish guts and old tires have become a regular part of the ice fishing scene, he said. Bags of human feces often are left behind to freeze into the ice and some anglers even leave their empty propane cylinders, he said.

Hirst said Lake of the Woods’ water quality is classified as impaired with excess nutrients, so fecal pollution is a concern. But “back of the napkin’’ calculations regarding impacts from various litter categories has suggested that water contamination from fish house garbage is less of a concern than landscape appearance.

Still, Hirst said, the Lake of the Woods Keep it Clean Committee is going strong and has attracted interest from other northern Minnesota lake groups. Lots of energy has gone into signage for the campaign, including fliers at local liquor stores and bait shops.

Radio and newspaper promotions also spread the word.

“It keeps people thinking of doing the right thing when they are on the lake,’’ Hirst said.

Salo said the DNR will dispatch up to a dozen conservation officers to Leech Lake next month for the 38th annual International Eelpout Festival in Walker.

Uncontained trash and leftover litter have been a chronic problem in the aftermath of that event. Salo said DNR officers will not only “work on the litter,’’ but also patrol for under-the-influence violations and game and fish law compliance.

In the Detroit Lakes area, out-of-control trash from ice anglers prompted the Fargo-Moorhead chapter of Muskies, Inc. to work out an informal arrangement with city officials for an end-of-season cleanup.

Brett Waldera, president of the club, said volunteers set aside a day when most icehouses have been removed from area lakes. They comb the ice on ATVs, pulling trailers.

He said the bulk of the litter is made up of plywood, lumber and tree stumps used for blocking purposes to keep shacks from freezing into the ice.

But the group has also picked up thousands of chewing tobacco tins, empty beer cans, discarded clothing and lots of plastic minnow bags containing excrement.

“We pile it up on shore,’’ Waldera said. “The city comes for it with a loader.’’

He said the volume of debris varies from year to year, depending on the length of the season.

“It’s not getting any better,’’ Waldera said. “If we didn’t volunteer for the cleanup, it would all sink to the bottom or wash up on someone’s beach or shoreline.’’