Four Canadian wolves were captured and airlifted to Lake Superior's Isle Royale National Park in Michigan, which doubled the current number of wolves in the area.
The National Park Service said it plans to take 20 to 30 wolves to Isle Royale over several years, AP reported, adding that the animals prey on moose, which have experienced a population boom since wolves left the area.
Scientists say that if the moose population continues to explode, they will over-eat trees and shrubs on the island. That will harm the environment and will likely trigger mass starvation.
"The relocation of Ontario wolves to Isle Royale National Park demonstrates our mutual commitment to conservation and we are happy to help Michigan restore balance to the island park," said John Yakabuski, who is the head of the Ontario Ministry of Natural Resources and Forestry.
There are about 1,500 moose on the island.
"On our first round, We knew that we wanted four to six wolves from Canada, so the ministry actually had a plan that if we could not get out to Michipicoten Island [on Lake Superior], then we would operate on the mainland," Phyllis Green, the Park Superintendent at Isle Royale National Park, told the CBC. "So two of the animals were obtained from the same pack outside of Wawa. And they actually have a rare coloration of black. Which is unusual and pretty significant in the wolf world based on some research."
According to Jolanta Kowalski, a spokesperson for the Ontario Ministry of Natural Resources and Forestry, two people fired nets at wolves from a helicopter to restrain the animals.
Winter storms prevented the operation until last week, AP reported.
Green added that it is necessary for diversity in the wolf population on the island.
"Actually what we need on Isle Royale is diverse genetics from wolves. We know that as a result of the last 60 years, where they can track most of the wolves that were on the island back to a single female, that too narrow of a line of genetics could ultimately lead to the demise of the population," she told the CBC.
No more wolves will be taken to the island this winter, park spokeswoman Liz Valencia told AP.
In 1980, the population peaked at 50 wolves before dropping off.
Last fall, four wolves were released on the island but one died, and another wolf walked to the mainland over an ice bridge that formed in February 2018, Fox59 reported.