Mingling with domesticated sheep could’ve caused disease outbreak among wild sheep, agency officials say
Alaska Fish and Game personnel killed two young Dall Sheep last week near Salcha, because the animals may have been exposed to a pathogen that could endanger the state’s declining Dall sheep population.
Alaska’s Dall sheep population has been falling statewide in recent years. So a couple of local Fish and Game officials are feeling conflicted over a policy that required them to kill two young male Dall sheep near Harding Lake on Aug. 5.
“It was a tough decision,” said Lincoln Parrett, Fish and Game’s regional supervisor. “You know, we don't want to kill wild animals that are apparently healthy.”
But Parrett said in this case, because of the potential of spreading disease, it was the right decision.
“In the end, the risk was just too great for us to take,” he said in an interview Wednesday. “We just felt like we had to do something, because of how poorly these sheep are doing statewide right now. They don’t need this on top of everything else.”
The concern was that the two sheep were exposed to a bacterium called Mycoplasma ovipneumoniae, or M. ovi, which causes pneumonia in Dall sheep and other wildlife. Parrett said that could’ve occurred in the neighborhood where the two animals had been hanging out.
“We had heard that basically there were multiple sets of domestic goats in that area that were not always contained,” he said.
Harding Lake is "a very unusual place” for Dall sheep, Parrett said. But area residents told him they’ve seen them around several times in recent years. He said they’re likely from the eastern Alaska Range or possibly came down from the uplands of nearby river drainages, including the Salcha River.
Parrett says some areas in the Lower 48 require people who raise goats to keep them fenced-in to prevent them from mingling with wild sheep -- especially males that may be looking to hook up with a domesticated ewe. Some jurisdictions require double fencelines to keep the wild and domesticated sheep from nuzzling, he said, because M. ovi exists mainly in the animals’ respiratory tract.
“It's not even an escape issue,” he added, “but just, like, their noses can't touch 'cause there's two fences separating them.
Fish and Game veterinarian Kimberlee Beckmen says those sorts of precautions demonstrate the level of concern over an outbreak of pneumonia that could devastate wild sheep populations.
“It kills Dall sheep,” she said. “And in the western states, there's many, many documentations of a wild bighorn sheep getting in with domestic sheep, picking up that M. ovi and then going back and it causing a mass mortality event.”
Alaska’s Dall sheep population fell by about 20 percent from 1990 to 2010, but since then the decline has slowed. But Parrett says some regional Dall sheep populations declined 50 percent to 70 percent, “even more in some isolated groups of sheep.”
He said in 2017, Fish and Game instituted the rule requiring the agency to kill Dall sheep exposed to domestic sheep. But that hasn’t been necessary in this part of Alaska -- until last week.
“We’re prepared for this type of event,” he added, “but we’ve actually had not had it happen, in the Interior at least.”
Beckmen said she, too, regrets that the agency had to kill the two Dall sheep. But she hopes necropsies conducted on the animals will help wildlife managers learn more about the disease.
“We took advantage of the opportunity, because these animals were fresh for their postmortems and they were complete. We don't usually get that,” she said Wednesday.
“So we had four veterinarians and took massive numbers of samples. … to make sure that we got all the science and data that we need that helps us monitor the health of Dall sheep populations.” She said the two Dall sheep “contributed greatly” to that effort
Beckmen hopes to have results of the necropsies in about four weeks. That’s about the same time that this year’s general Dall sheep hunting season will be winding down. The season opened last Sunday.
