PENTICTON — The bighorn sheep population in the Ashnola-Similkameen region is dropping. Biologists haven’t been able to pinpoint an exact cause, but one of the factors threatening the herds may be a contagious mite called Psoroptes. In a 2013 report written by the Ministry of Forests, Lands and Natural Resource Operations, it estimates that 56% of the bighorn sheep are infested by the mites. The Ministry says that over time, the disease may have implications on the population’s health.
“They’re basically insects that are related to lice, but occupy the surface of the skin and some of them burrow into the skin. In this case, they live in the ear canals of sheep,” explains Helen Schwantje, the wildlife veterinarian for the provincial government.
The Ministry confirmed the first case of Psoroptes in 2011, when a very sick ram was observed near Olalla.
Since then, it has conducted two aerial surveys to learn how widespread it is.
But it cannot determine if the mites are the only reason for the population decline.
“Bighorn sheep are pretty sensitive animals and helicopters can cause pretty significant stresses to them,” says Schwantje.
So last fall, the Ministry of Environment asked an advanced helicopter flying school, HNZ Topflight, to avoid a section in the Snowy Protected Area, a region west of the Okanagan Valley.
Chief Flying Instructor Tim Simmons says the limitation isn’t affecting their training program so far.
“We have adjusted our flight paths and have been asked to avoid a certain area that’s sensitive to the sheep, a lambing area, and we’ve been happy to comply with that,” he says.
Simmons says if more restrictions are put on the school, then it would affect their business.
The Ministry says there will be a follow-up meeting within the next couple of months.
It says it is collaborating with the flight school to minimize the impacts on the bighorn sheep population.
It will also investigate the exact cause of threat because the mites may not be the only factor.
“If you look at the literature or talk to the people in the States, where they have this parasite epidemic in the bighorn sheep population, many of those populations are still existing today,” explains Schwantje.
Another aerial survey will be done later this year to learn how many sheep are affected by this disease.
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