By Joseph Robertia
For years many people have anecdotally suggested there are more brown bears on the Kenai Peninsula than the thrown-about estimate of 250 to 300. Last week the Kenai National Wildlife Refuge released findings from its DNA-based mark-recapture study that confirmed the sentiment, with a new estimate of 624 brown bears.
But, does this mean that there are more bears, much less, as some suggest, too many bears on the peninsula?
“Just because we have 624 now doesn’t necessarily mean there are more bears,” said John Morton, a supervisory biologist with the Kenai National Wildlife Refuge who oversaw the project. Rather, he said that the 624 number may simply reflect a more accurate estimate for a population number that has been here for years.
“It’s still at the low end for coastal brown bears, and not really a lot for the entire peninsula when you consider its overall size and resources. But it is a more solid and scientifically based estimate compared to the 250 to 300, which was useful at the time, but was based on densities from the Susitna area.”
The new estimate — comprised of 200 males, 200 females and 224 cubs — was derived after refuge biologists spent more than a month collecting hair samples in 2010. Bear habitat across the peninsula was divided into cells forming a grid. Each cell had a lure station baited with a mixture of fermented fish oil and cow’s blood, surrounded by barbed wire. As the bruins passed the wire — stepping over or going under it — their hair got caught in the barbs.
Using two helicopters with two, four-person crews assigned to each one, the two crews leapfrogged each other from one sampling point to another, deploying and retrieving traps and collecting hair samples, from 16 to 20 hair stations each day. That equates to checking each station about every seven to 10 days. The number of hair samples retrieved varied depending on location. Some stations had zero and some stations have had up to 721, but 12 samples seems to be the average.
“We got more than 11,000 hair samples in the end,” Morton said. “It was a lot of work, and I’m thankful that — given the
nature of what we were doing, landing helicopters in remote areas where we knew there were bears — I’m glad no one was hurt.”
Despite the arduous nature of collecting the hair samples, the real hard work began when the collection phase was over. The hair samples were sent to a lab in British Columbia and had to be separated — brown bears from blacks, which took months. Then the samples had to be analyzed further and the data reviewed for accuracy. It was these latter points that resulted in the two-year delay of releasing the final number of 624.
“We took months to crunch the numbers, but it was best to have it peer-reviewed by people outside the refuge and outside of Alaska,” Morton said.
Having a more accurate estimate will bring some changes related to the brown bear population, Morton said, but it’s tough to say for certain what those may be, since state and federal wildlife managers often have different ideas and directives about how to manage bruins.
“We manage game collaboratively with the state, but at the refuge, our mandate is to conserve wildlife. We’re not interested in artificially inflating or deflating a population, so for us, I don’t see anything being too different in the short run for how we manage brown bears.”
However, the state establishes the number of bears that can be harvested annually, including through hunting. This
number is based, at least in part, on the bear population’s size. As such, with 624 rather than 300 bears now known to be on the peninsula, there could be more proposals made through the Alaska Board of Game to liberalize hunting of bears.
“The more data we have and the more accurate that data are, the better it is for us, so this will give us something to work from now,” said Jeff Selinger, a wildlife manager with the Alaska Department of Fish Game.
Selinger said that he had long thought the 250 to 300 population estimate was faulty.
“Looking at the food availability here, the fish escapements, the number of incidents and mortalities we were seeing each year, and what we saw with our own data — the 250 to 300 number just didn’t seem completely accurate,” he said.
Also, the state has for years been conducting its own radio-telemetry study of brown bears. The number of bears in the study changes from year to year as animals die or slip out of their collars, but at any given time there are 20 and 40 adult female bears being monitored. Selinger said that combining Fish and Game’s own ongoing research results with the new data from the refuge should allow for a more accurate and comprehensive approach for managing bruins in the future.
“The population number is a snapshot in time, but there are other factors that are important to us, too. We still have more to learn about the population parameters, such as the age of first reproduction, the average litter size and the survival of the different sex and age classes, just to name a few characteristics,” he said. “But, with what we have now, we can look at where the gaps are in what we know to determine where we should go in the future.”
These other figures can be tough to compile, though, since it can take so long for changes in the bear population to show up, and there are so many variables that can affect their population.
“Unlike moose, which you can predict will have one to two calves a year, every year, bear sows can have a litter they could keep for two to three years, or they could be disrupted or lose cubs and become pregnant again in the time,” he said.
And even though a more precise population number is now known, Selinger said that this number will be perceived in different ways by the public, which can also affect the bear population number though hunting, defense of life and property shootings and other causes of bear mortality.
“For us wildlife managers, it’s better to know there were more out there than we thought,” he said. “But for the general public, we’ll still have people on both sides of the fence and in between. For some 624 is too many, for others 624 won’t be enough.”
While the next Board of Game meeting to discuss Southcentral topics, including the peninsula, isn’t until mid-March, the first brown bear of the year was already spotted late last week. According to Selinger, a homeowner in the Aurora Heights subdivision in Nikiski saw a brown bear in the morning while on his way outside to go to work.
“The warm weather we had a few weeks ago could have stirred it,” Selinger said, adding that the cold weather spell that followed may have been enough to send the bruin back to bed, since there have been no further reports.
“Hopefully it settled back down to sleep for a few more months,” he said. “But, the incident speaks to the importance of minimizing attractants year-round.”