© Daniel J. Cox/Natural Exposures.com
9/14/2015 6:27:02 PM
Feasting at Whale Bone Piles
Autumn in the Arctic brings crisp weather, brilliant tundra colors, migrating birds and wildlife - and, in parts of northern Alaska, bowhead whale remains from successful Inuit community harvests. The remains attract landlocked polar bears, which gather to feast on the scraps: a significant source of calories for some bears.
"Consistently available harvest remains in known locations are a fairly recent phenomenon," says Geoff York, PBI's senior director of conservation. "Dozens of polar bears can congregate at the bone piles, fattening up after a summer of fasting on shore. The largest bears I've ever handled were in the vicinity of Kaktovik, Alaska in the autumn - truly impressive!"
North Slope hunters have traditionally taken bowhead whales during their migrations in both in spring and fall as part of their subsistence lifestyle. In the past, more whale harvests occurred in the spring, and hunters processed most of their catch on the sea ice, letting the scraps and bones drift away and eventually return to the sea.
Loss of sea ice and increasingly open waters in the late summer and fall have allowed the fall whale harvest to become more successful and predictable, while spring hunting has become more challenging in some years due to thin ice. Fall harvests also means whales are increasingly processed on shore, leaving behind remains that can attract scavenging polar bears and other wildlife.
The phenomenon takes places now every fall in three North Slope communities: Kaktovik, Point Barrow, and on Nuiqsut's Cross Island (a hunting camp 10 miles offshore from the central coast).
"A shift towards more reliable fall bowhead harvest combined with increasing use of land during the ice-free season by polar bears has led some bears to anticipate this high-calorie resource, resulting in large seasonal congregations even before whale remains are available," says York. "In Barrow and Kaktovik, this can bring more polar bears closer to communities for an extended period of time and create the potential for increased bear-human interaction."
Polar bears on the southern Beaufort Sea traditionally spent most if not all of the summer out on the sea ice. But the summer sea ice now retreats hundreds of miles from the northern Alaskan coast, leading a growing number of polar bears in that population to come ashore, where they wait for the ice to return in late fall.
Studies by the USGS show that polar bears that swim to shore in this area stay longer than the few polar bears that ventured onshore several decades ago: an average of 47 days compared with stays of about seven days in the late 1980s and early 1990s. Their research also indicates that percentage of bears coming ashore in summer and fall to take advantage of this resource has increased from 4% in the mid-2000s to 15% in recent years.
The extra calories are clearly helping the bears that have discovered the bounty, but questions remain about the benefits going forward. More polar bears near villages could lead to increased human-polar bear conflicts, especially if the number of bears outstrips the amount of food. A review of polar bear-human conflict data by the Range States Conflict Working Group appears to support this concern. Another potential problem is an increase in disease exposure as large congregations of polar bears interact with one another, brown bears, fox, wolverine, and a variety of scavenging birds.
The community of Barrow began actively managing their harvest remains after experiencing higher than average years of polar bears around town - with great success. Kaktovik is actively looking at options to relocate its bone pile further away from the community to enhance community and bear safety. Across Alaska, communities and those working in polar bear country are also increasing their investment in and awareness of conflict reduction.
For now, though, the blubbery scraps are a welcome supplement to a small percentage of bears during the lean autumn season.