Though born too late to see American Indians chop holes in ice-covered lakes to spear fish, Irv Rubbelke has lived long enough to witness firsthand nearly all of the rest of Minnesota’s ice-fishing history.

Rubbelke, of St. Paul, will be 100 years old in January.

“When we fished in winter as kids, we used chisels to cut holes in the ice and sat on buckets in the open,’’ Rubbelke said. “We fished for crappies. But there weren’t many bait stores. We sent away for most of our worms.’’

How times have changed.

Today, fishing is Minnesota’s most popular winter sport. In December through February, tens of thousands of fishing shelters typically dot ice-covered lakes from Winona in the southeast to Warroad on the Canadian border.

On Lake Mille Lacs — historically the state’s premier walleye fishery, and the site, many winters, of more than 5,000 fish houses — Department of Natural Resources fisheries managers estimate up to 60 percent of the lake’s annual fishing pressure is applied by ice anglers.

Yet only 10 percent to 15 percent of the total annual Mille Lacs walleye harvest occurs in winter, suggesting the sport’s attraction differs in important ways from summer fishing.

“There’s something about being on the ice in winter that’s calming,’’ said Spider Johnson, who guides summer anglers on giant Upper Red Lake in northwest Minnesota and rents fish houses there in winter.

If that’s true, then Dave Genz should be nearly comatose, given how many days he spends on hard water in winter.

Considered a “father’’ of modern ice fishing, Genz, 66, of St. Cloud, was a teenager when his dad, Arnie, constructed what might have been the world’s first portable ice-fishing shelter — a development that foretold the revolution of the sport in the past 50 years.

“Dad built a structure that could be pulled onto the ice and moved around relatively easily in an attempt to find fish wherever they were biting,’’ Genz said. “It had two solid plywood ends and a plywood floor, with the other sides and top made of canvas.’’

Most winter fish houses until then were entirely constructed of leftover wood or other scrap, usually over two heavy wooden skids.

Once on a lake, these shelters were too cumbersome to move, considering their heft. Recalled Rubbelke, “I made my first ‘fish house’ in the 1930s out of scrap lumber. But back then we didn’t have cars that could pull the houses onto the lake. And even if we had, it wasn’t legal to drive on the lakes at that time.’’

Genz’s uncle, Gene Lease, of Sauk Rapids, rocketed the portable fish house idea forward in the 1960s when he developed the sport’s first flip-over shelter.

A sled with shaped metal rods over which a three-sided awning was fitted, the flip-over shelter blocked the winter wind while increasing anglers’ mobility.

“Even when I was a kid I didn’t like sitting in one spot when the fish weren’t biting,’’ Genz said. “It was too slow for me. So I’d go outside and cut one hole and another, until I found fish I could catch.’’

Much of this “hole cutting’’ was still being done with chisels — heavy steel posts about 5 feet long with pointed ends. Anglers would lift the chisels straight up before driving their sharp ends into the ice, an exercise that might be repeated 50 times before water was reached.

Revolution gains speed

Returning from military service in the 1970s, Genz began to manufacture flip-over portable ice fishing shelters similar to the ones his uncle developed. A conduit bender was used to form the metal rods that bolted onto a small sled.

His wife, Patsy, sewed the cotton duck coverings.

“She sewed five the first year, then 20, then 80,’’ Genz said. The shelters were sold in Twin Cities sporting goods stores under the Fish Trap name.

Other new ice fishing gear also was being developed.

“Jig sticks,’’ for example — quite literally wooden sticks rigged with stiff line that were the winter fishing rods of their time — were replaced by short fiberglass rods and metal reels.

“Then one day in 1982 I saw ice fishing leave the Stone Age and enter the Space Age,’’ Genz said.

While employing what was known at the time as a Sitex (now Twin Cities-based Vexilar) flasher, or depth finder, Genz watched in amazement as the gadget showed his jig and bait descend into the watery depths.

“The first ice fishing show was held in Madison, Wis., in the mid-1980s or so,’’ Genz said. “By then I was advocating ice-fishing systems, in which portable shelters and electronics were the major components.

“But not everyone understood the concept, and the first year, I didn’t sell much,’’ he said. “But the second year, people were catching on because In-Fisherman magazine started writing about my system. I sold everything I had by noon.’’

In the years since, the twin concepts of mobility and comfort have been continually refined.

“Permanent’’ or “skid’’ ice fishing houses are still popular. But today similar shelters on retractable wheels also are commonplace; shelters that can offer the conveniences of home, including beds, bathrooms, TVs, ovens and stoves, and that also can be moved fairly easily.

Yet Genz, who today represents Clam Corp., manufacturer of portable winter shelters and other ice fishing gear, still advocates mobility above all.

Mille Lacs fishing guide Tony Roach agrees. He might drill 100 ice holes in a day while leading clients across Mille Lacs in search of hungry fish.

Aiding Roach are high-powered, lightweight augers with laser-sharp blades, GPS systems that pinpoint hot spots and electronics that not only spot walleyes below the surface, but can display jigs and baits as they near a fish’s mouth.

The ice-fishing revolution will continue, Genz believes, who at the big St. Paul ice fishing show last weekend displayed a Clam portable shelter hooked to a customized snowmobile featuring a Star Wars-like assortment of gizmos, including an underwater camera.

“When fully electrified clothing comes on the market, that will really help,’’ he said. “Then no one will get cold.’’