A recovery program that uses nasal swabs to test bighorn sheep for bacteria is proving effective for a meta-population herd near the Fraser River.
Jeremy Ayotte, of Phyla Biological Consulting, said the program has resulted in more lambs surviving the spring and late summer along the Fraser River, following a sharp decline since the 1990s.
“It’s proven to be quite effective,” Ayotte said, noting blood samples conducted on one-and-a-half-year-old lambs didn’t see any sign of mycoplasma ovipneumoniae (Movi). “It suggests that the bacteria is not in the population anymore.”
The program was started on both sides of the Fraser River from Lillooet to Williams Lake in 2019 after the declining population was confirmed to be caused by the bacteria, which is passed on to wild sheep from domestic populations. The ewes that survive the disease give it to new lambs, who tend to be fine while they’re on their mother’s milk and getting antibodies, but die from pneumonia as soon as they’re weaned.
“It’s quite well known wild sheep and domestic sheep don’t mix,” Ayotte said. “That bacteria is brought onto the land and for the wild population, it will end up killing a lot of them at first. It’s like a Typhoid Mary situation.”
In order to test them, the sheep are helicopter-captured and administered nasal swabs similar to the PCR tests for COVID, which pick up the presence of the bacteria. Sheep that have the bacteria are then culled from the herd, giving their offspring and others a better chance at survival.
Several sheep were recently removed from the herd along the Fraser River after testing positive. As respiratory illness doesn’t affect the meat, it will be donated to those who need it.
“It’s a brutal project for the biologists working on it,” Ayotte said. “It’s always hard to kill animals to try and save them.”
Ayotte said the program, which had been marching its way north on the west of the river near Lillooet, will now head south on the east side near Clinton.
The focus now is on keeping the domestic sheep and bighorn sheep apart.
“We’re really pushing hard and working with government to come up with policies to support that,” he said. “We’re trying to support farmers in different ways – to realize there is this risk to our wildlife.”
He noted the Fraser River area is a meta-population for California bighorn sheep, with more than 60 per cent of Canada’s population.
“The Fraser River is amazing bighorn sheep habitat, with steep rugged terrain, and grasslands. Back in the ’90s there were thousands more sheep than there are now. We’re hoping there will be a day when we will see those numbers back again.”
The project, which costs more than $100,000 a year to capture, test and analyze the samples, is funded by the Wild Sheep Foundation in the U.S., the Wild Sheep Society of B.C. and the Habitat Trust Foundation.