A small parasite is taking a big bite out of northern New England’s moose population.

Across the region, moose are falling prey to the winter tick – in some areas at an alarming rate. As Maine prepares for its annual moose-hunt lottery Saturday, the state has taken significant measures to protect its herd.

This spring, the Department of Inland Fisheries and Wildlife reduced the number of moose permits for the 2014 fall hunt by nearly 25 percent – from 4,085, the number set in March, to 3,095, the fewest issued since 2009.

“We just made it through a horrible winter for winter ticks (killing moose),” said Maine’s moose biologist, Lee Kantar. “We’re extremely concerned with what the future holds.”

The moose lottery will begin at 3 p.m. Saturday at the University of Maine at Presque Isle. Permits will be allocated in 25 wildlife management districts encompassing more than 21,000 square miles of moose habitat.

Winter ticks are parasites that attack hoofed animals, especially moose. They are larger than most mites – growing to more than a half-inch long at their peak, when they feed on moose in late winter. Climate change is cited as one reason why there are now more winter ticks.

In Maine, winter ticks have been documented by biologists since the 1930s. Last fall, winter-tick counts on harvested moose were higher than in any year since the state started monitoring them in 2006.

In January, biologists began a five-year study involving 60 moose, affixed with radio collars, around Moosehead Lake. Half of those moose – 21 calves and nine adults – died this spring.

Tissue analysis won’t be back from the lab for several weeks, but Kantar said the moose, especially the calves, showed signs of anemia and mortality caused by winter ticks.

“When you find a calf lying dead and it has nothing else wrong with it, no broken bones, and there are signs of anemia, winter ticks are the most likely contributing factor to why that animal died,” Kantar said.

In neighboring New Hampshire, hunters and biologists are worried.

John Lanier, a forester and hunter who lives in Columbia, New Hampshire, 20 minutes from the Canadian border, said moose have all but vanished there.

“The moose population has gone down, there is no doubt about it,” Lanier said. “I was looking at one the other day that was shot because it was about to die. It had tens of thousands of ticks on it. It didn’t bleed. The ticks had taken all its blood.”

Kristine Rines, who has been New Hampshire’s moose biologist for the past 20 years, said the situation there is dire.

“If we continue to have shorter winters, this increase in parasitism will result in increased mortality,” she said. “It could have some fairly significant impact on our ability to maintain moose on the landscape.”

Rines said moose in New Hampshire are at the southern end of their range, so they are susceptible to warm-weather parasites like ticks. In response, New Hampshire will issue just 124 moose hunting permits this year – down from 675 a decade ago.

“Winter tick and brainworm right now are the big drivers of our population. Both of those parasites survive the shorter winters very well,” Rines said. “It’s kind of discouraging. We may not be able to hold moose over the long term.”

In January, Kantar told the Portland Press Herald that Maine’s moose herd is less susceptible to winter ticks than New Hampshire’s because it roams in a more northerly climate. He now says he’s not sure.

“I certainly hope that the more north you go, the less of an issue you have with winter ticks,” he said. “We have to see what that looks like. In the Province of Quebec, they’ve had issues along the Vermont border, but less in Quebec as they get farther north. It’s complex.”

Maine biologists determined in 2012 that the state’s moose population was as high as 76,000, after the first comprehensive aerial survey of the herd, said Mark Latti, spokesman for the Department of Inland Fisheries and Wildlife. It is the largest moose population in the continental United States, far greater than New Hampshire’s and Vermont’s combined.

In Vermont, the winter tick is a significant concern, said Mark Scott, director of wildlife in the Vermont Fish and Wildlife Department.

A decade ago, Vermont biologists increased moose hunting permits to reduce the population because they believe that a smaller moose herd – now estimated at 2,300 statewide – is less susceptible to the parasite. In 2010, with the herd at the level it wanted, Vermont began to decrease its moose permits to around 300. This year, 335 will be issued.

“We’re not seeing the severity of ticks. Research shows the more moose you have, the more hosts the ticks have to feed on, the worse the problem,” Scott said.

But he’s still concerned about how climate change will affect the population of ticks. “We are closely paying attention to Maine and New Hampshire and other places,” he said.

Moose herds are dwindling elsewhere in North America.

A 52 percent decline in Minnesota’s herd since 2010 prompted the state’s Department of Natural Resources to close its hunt in 2013. The department’s website said the season was closed because: “DNR wildlife managers did not anticipate such an alarming decline in the overall moose population.”

In Ontario, the Ministry of Natural Resources reports in a special alert box on its website that “moose populations in North America are changing, and here in Ontario the herd is experiencing some pressures in some areas,” and “potential changes to hunting regulations may be considered in some areas in the future.”

In Maine, moose hunting guide David Kelso said moose are on the decline in Aroostook County, along the state’s border with Canada.

“Moose are on the southern range of moose territory. When an animal is on the southern range, it becomes more susceptible to parasites,” Kelso said. “Even in Quebec there is a problem with ticks. I don’t think we’ll end up as bad as New Hampshire unless we overhunt. That’s my big concern.”