A 2010 federally sponsored study is the first to deliver a reliable count of the Kenai Peninsula’s brown bear population. Last week a Kenai National Wildlife biologist explained the study during a presentation at the Pratt Museum in Homer. The Museum is preparing to launch a new summer exhibit all about bears, specifically brown and black bears.
The number of brown bears on the Kenai Peninsula fell from about 582 to fewer than 500 between 2010 and 2015. That’s according to John Morton, a Kenai National Wildlife Refuge biologist.
“It has to do with the fact that harvests have been liberalized by the Board of Game since 2012. So our harvests [have been] higher in the last couple of years, particularly in 2013 and 2014,” said Morton.
The U.S. Fish and Wildlife Service and the U.S. Forest Service paid for Morton and his team to spend part of their summer counting brown bears using a method called mark recapture. Mark recapture is pretty much what it sounds like. The researchers caught the animals, marked them, released them and then they tried to recapture the animals they’d marked. Morton’s team marked the bears by collecting their hair and analyzing their DNA.
“And the key here is it’s not the number of animals we detect with DNA it’s actually our recapture rates. That goes into a model and we base our population estimate not on the number of bears we detect but actually on the number of bears we mark,” said Morton. “Obviously you can see from the slides it was pretty complicated both logistically and statistically.”
Morton says before this count there had never been an “empirically based population estimate of Kenai brown bears.” The dense tree cover on the peninsula made “conventional” aerial surveys impractical.
