A new aerial survey of moose in northeastern Minnesota shows the population has dropped dramatically, prompting the Minnesota Department of Natural Resources to cancel this year's moose hunting season, officials announced Wednesday.
The survey showed a population decline of 35 percent in the past year. Since 2010, the moose population has declined 52 percent, the DNR said. The aerial survey conducted in January found about 2,760 moose, down from 4,230 in 2012.
The DNR said it will not open a moose hunting season unless the population recovers.
"There's just a plummeting population here," DNR Commissioner Tom Landwehr said during a news conference. "We, as all Minnesotans, I think, are very concerned about the moose population."
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Landwehr said recent moose hunts have had very little effect on the population, but he said because the hunt is the state's only way to prevent mortality, officials decided to cancel the hunt. The DNR is also talking with tribal leaders in the moose range about their hunts, Landwehr said.
DNR officials said they are trying to find out why the population is declining. Researchers are nearly finished placing GPS collars on 100 moose in northeastern Minnesota to study adult mortality. The research will continue in May with the collaring of 50 calves to learn more about the causes of calf mortality.
DNR wildlife manager Lou Cornicelli said the project will give researchers better information about why a moose has died. If a collared moose dies, research teams will be able to quickly collect the carcass and send it to the University of Minnesota for a necropsy, he said.
Cornicelli said the research is the largest study of its kind on moose and will have national and international significance.
"Other states and entities are looking at our technology to see if they can apply it," he said.
Cornicelli said survey error was the first thing DNR biologists considered when looking at this year's numbers. The aerial survey involves flying over randomly selected areas of the state's northeastern Moose range each year and counting animals. Cornicelli said the method used to estimate the population has been used consistently.
"The precision of our survey wasn't out of balance from what it's been in previous years, so you have to accept the numbers for what they are, even though there is always going to be uncertainty," Cornicelli said. "The degree of decline is certainly more than we would have predicted."
Climate change, which has caused a rise in temperatures, has been suggested as one possible cause, but Cornicelli said it isn't that simple.
"There's a lot of unknowns with that," he said.
Diseases, parasites and changing habitat have also been cited as possible factors contributing to the moose population decline.
Steve Merchant, DNR wildlife populations and regulations manager, said at this rate of decline, it will only take a few years for the moose population in northeastern Minnesota to reach a low enough number that makes it difficult to survey the population. It's what happened to the northwestern Minnesota moose population.
"With those kind of numbers it would come much more quickly than 2020 even," Merchant said.