National Park Service photo The third wolf brought to Isle Royale National Park is seen in this 2019 file photo. The wolf was part of the translocation of wolf to the island. According to preliminary findings the number of wolves currently in the park is at a near record.

HOUGHTON — Isle Royale’s wolf population is surging to a near record high while the moose population is plummeting, the 2026 Isle Royale Winter survey study found.

The long-running survey was conducted January 22 through March 3 and preliminary findings published Monday, by Michigan Technological University’s College of Forest Resources and Environmental Science CFRES). Researchers studied the increase of the wolf population since 2024.

Meanwhile, the study shows the moose population has plummeted by 75% to 524, down from the 2,000 recorded in 2019. Wolves killed nearly one-quarter of the moose population over the past year. Among other findings, for the first time since the project began in 1958, scientists observed no moose calves during the winter survey.

The sharp decline in the moose population has largely been driven by an increase in wolf predation, the study found. In 2018 and 2019, 19 wolves were translocated to Isle Royale by the National Park Service to prevent the island’s wolf population from becoming extinct.

Currently the wolf population is composed of three packs, with 10 to 13 wolves in each pack. All three packs — the West Pack, East Pack and Northeast Pack — successfully raised pups last year and appear likely to produce pups again this spring.

Rolf Peterson, research professor at CRFES, has been studying the wildlife on Isle Royale for more than 50 years, having joined the Wolf-Moose Project at Purdue University in 1970. He brought the project to Michigan Tech in 1975, where he continues to co-lead, along with Sarah Hoy and fellow CFRES researcher John Vucetich.

Peterson said while the moose population is rapidly declining, the wolf population has increased by seven, up from 30 just two years ago.

“Anything from 30 wolves and up is pretty high,” he said, “so 30 or 40, or even 28 is high. What counts is how efficiently those packs can kill moose and they’ve been pretty efficient in recent years.”

Another subject of study has been the decline of balsam fir on the island, a staple and preferred food for moose. This is part of a longterm decline because of the presence of high-density moose populations, said Peterson.

“The Balsam fir has been declining on the western half of Isle Royale for several decades,” he said. “In the last years, it’s been particularly at risk because of high (moose) population. It hit these trees 10 years ago, and they grow so slowly.”

Currently there are about 1,200 individual trees tagged, said Peterson, and they will be studied this summer to determine if they are still alive and how tall they are.

“I mean, these are three and four feet tall. They’ve been hammered by moose, particularly in the early years of their growth,” he said, “and so they’re just barely able to hang on and they really haven’t recovered their growth yet.”

Michigan Tech researchers were initially scheduled to return to Isle Royale this week to begin summer fieldwork. Peterson, who will again lead the team, said that schedule is subject to change.

“It depends on the weather and boat schedules,” he said, “so, things are being pushed back because of ice and strong winds Monday and Tuesday are gumming up the schedule.”

Peterson said the summer research will focus on the status of Balsam Fir and on the declining moose population.

“There are four student interns devoted to Balsam fir studies, then we’ve got about 60 citizen scientists who roam the island extensively searching for dead moose.”

“Mostly looking at moose and balsam fir trees, particularly dead moose. We want to find out details on the kind of moose that are dying and what they’re dying from. A lot of that is dealing with the status of balsam fir trees that are being browsed by moose in the wintertime.”

The citizen scientists include members of Moosewatch, along with other partners.

The survey found that wolf predation on moose rates are near the highest level ever observed.

“The wolf/moose system is sort of at the edge of where it’s ever been since the last century,” Peterson said, “so (to say) it’ll be a tipping point is not an exaggeration.”