BANGOR — When state wildlife officials petitioned to allow trapping for fisher and pine marten in areas where threatened Canada lynx live, they were required to formulate a plan that would minimize the chances of lynx being accidentally captured in those traps. That petition was approved in November.

However, on Monday, the Department of Inland Fisheries and Wildlife ordered the halt of all above-ground trapping in the northern half of the state in response to the death of two Canada lynx that were killed in traps this fall.

“It is surprising (that two lynx died over such a short period of time),” said Jennifer Vashon, a Maine DIF&W biologist. “When we wrote that plan (that was submitted to the U.S. Fish and Wildlife Service and approved on Nov. 4), what we relied on was the data that we had. So the whole plan is based on the department’s monitoring of lynx take since 2000.”

The federal Endangered Species Act defines “take” as “to harass, harm, pursue, hunt, shoot, wound, kill, trap, capture or collect, or to attempt to engage in such conduct.”

According to the plan, Maine trappers were allowed to continue using lethal traps in areas where lynx live, but the accidental take of lynx was to be closely monitored. But if certain circumstances changed, the DIF&W was required to immediately implement new regulations if a second lynx was killed in a legally set trap.

The lynx deaths triggered those mandatory changes to the regulations. In the USFWS’s explanation of the incidental take plan, the agency said that the DIF&W expected three or fewer lynx to die in legally set traps over the 15 years that followed the plan’s implementation.

So what happened?

The DIF&W said in a press release that the two lynx deaths, which died in traps set in Oxbow Plantation and in St. Croix Township, both in Aroostook County, were the first caused by trapping in six years. Meanwhile, during the same time period since 2009, 26 lynx have been killed by motor vehicles.

On Friday, Vashon, the DIF&W biologist who has led much of the state’s lynx research, said that the data she helped generate in the early 2000s, along with data on incidental lynx mortality over the past several years, doesn’t likely reflect the current lynx population. Work to be conducted on a new study in the coming months will help fill that data gap, she said.

Vashon said although the state plans to continue lynx research this winter, and hopes to come up with a more accurate population estimate, the available data and the estimate developed in 2006 doesn’t reflect the fact that lynx populations are likely at a historic high.

“Everything’s indicating that the lynx population has grown since our last estimate,” she said. “So we’re going to go out there and collect data to update our estimate.”

Vashon wouldn’t guess at the lynx population, but she said reaching a more accurate estimate will help the state work with the USFWS to adjust the incidental take plan.

Could lynx no longer be endangered?

Vashon also said the federal agency is working, with state help, to fulfill another requirement of the Endangered Species Act: The USFWS has to determine criteria that could be used to remove lynx from the list as a threatened species.

“The (USFWS), because (lynx) are listed, needs to come up with a recovery plan for lynx, because without a recovery plan, lynx will never be de-listed,” Vashon said. “They will come up with objectives for recovery. We’re working diligently to provide them with the data to help them develop the plan, identify criteria for de-listing, and then assess whether or not our population has met those criteria.”

According to the USFWS website, lynx were federally listed as a threatened species under the Endangered Species Act in 2000. Critical habitat — areas that were naturally occupied by lynx at the time of the Endangered Species Act listing — including 11,162 square miles in Maine, was designated in 2006, and revised three years later.

A call to USFWS biologist Mark McCollough was not immediately returned.

Vashon conceded that with more lynx on the landscape than the current estimate of 750 to 1,000 adults, the incidental “take” of lynx could be expected to rise above the limits set in the incidental take plan.

Perspective from the field

Brian Donaghy, a trapper from Unity, said he is convinced that the number of lynx that have been inadvertently killed in traps can be explained quite simply: The population has swelled.

“Anybody who spends any time out in the woods knows that the forestry practices haven’t changed [since the estimate was made]. If anything, they’re cutting even more. And the lynx population is only going to continue to benefit from that.”

Lynx populations grow when their primary food source — snowshoe hares — are plentiful and when suitable habitat is available. Donaghy said he sees lynx tracks everywhere when he’s working his trap line. Even five years ago, that wasn’t the case.

Therefore, he thinks the lynx population has exploded.

“The cutting practices we have now have created an artificial lynx habitat that’s not historic to Maine,” Donaghy said.

According to the USFWS, northern Maine has an abundance of lynx habitat, which includes large areas of “young, dense stands of spruce and fir approximately 12 to 30 years after a major forest disturbance (clear cutting, fire, insect damage).”

Just across the border, lynx are plentiful enough that the province of Quebec allows limited trapping of the species.