Minnesota’s great spearfishing mystery has been solved.

Fisheries managers, resort owners and even spearers themselves were shocked to see the sale of spearing licenses jump by 8,000, or a whopping 44 percent, this year after decades of flat or declining sales.

Some speculated that the opening of Lake Mille Lacs to northern pike spearers for the first time in 32 years may have prompted the spike. Others cited a recent change in state law that required senior citizens to buy spearing licenses.

Both, it turns out, were likely factors, but officials say there were others, too.

After examining license sales data and mulling over the puzzle, Department of Natural Resources officials now believe there were multiple reasons why the agency sold more than 26,000 spearing licenses this season. Among them: expanding the number of lakes where spearing is allowed (including Mille Lacs) lower-priced spearing licenses, requiring seniors to buy licenses and ideal ice conditions and a lack of snow, which allowed spearers and anglers to travel unimpeded on ice beginning in November.

“Certainly the seniors contributed and Mille Lacs contributed [to the increase], but they weren’t the whole story,” said Ed Boggess, DNR Fish and Wildlife Division director. “It was puzzling at first, but it was the coming together of all of these factors.”

Terrible ice conditions last year also played a major role in the mystery.

Here’s what happened:

• A law change on March 1, 2013 reduced the cost of a spearing license, then $17, to $5, and made them free for youths under 18. As had been the case for years, residents age 65 and older didn’t need a spearing license. The cost was reduced because spearers also need an angling license.

• In December 2013 the DNR opened 12 lakes, scattered around the state, to spearing that previously had been closed.

• Another law change on March 1, 2013 required residents age 18 to 89 to have both a spearing license and an angling license to spear, which meant spearers age 65 to 89 had to buy spearing licenses for the first time. DNR license sales data shows the agency sold about 2,000 more licenses to people age 65 and older. But that only accounts for a portion of the 8,000-license increase. Increased sales occurred across all age groups, including a 2,800 increase in licenses bought by 20- to 40-year-olds.

• Heavy snow hit in November and December 2013, greatly hampering spearers (and ice anglers) and likely negating any increase in spearing license sales that would have occurred in 2013 because of those significant spearing law changes.

• This season, Mille Lacs, where northerns have been protected by a spearing ban, was opened to spearers, and, encouraged by a high population of big pike and ideal ice conditions, spearers flocked there. The DNR estimates as many as 5,000 spearers may have fished the lake.

• Perfect spearing weather froze lakes early, encouraging spearers to buy licenses and get out on the ice. “We had January temperatures in November,” Boggess said. “We had good ice early, and never did have snow to reduce mobility.”

All of those factors, and possibly others, likely resulted in the surge of license sales.

“That makes a lot of sense,” said Tim Spreck of Stillwater, lobbyist and past president of the Minnesota Darkhouse and Angling Association.

“I think the other thing I would throw in is an increase in interest from young people. I’m seeing a ton of people in their 20s taking up the sport,” he said.

Added Spreck: “We’re happy because the sport is one of the new things out there, yet one of our oldest forms of harvest.”

Meanwhile, the DNR’s proposed Game and Fish Bill at the Legislature that would open up another 12 lakes to spearing — including some major Twin Cities area lakes, including Bald Eagle, Rebecca, Minnetonka and Forest.

Officials say the spearing bans on those lakes no longer serve a management function. Most of the bans were put in place in the 1970s or 1980s to protect muskies — which were and still are illegal to spear.