Western Arctic caribou herd has increased

Kristen Nelson

Petroleum News

Alaska’s largest caribou herd, the western Arctic herd, is showing signs of growth after years of decline. The Department of Fish and Game’s Division of Wildlife Conservation said Jan. 10 that last summer’s photo census of the herd produced a count of 239,055 animals, resulting in an estimate of 259,000 for the total herd, up from 201,000 caribou a year ago.

The western herd is one of four in Alaska and roams an area of some 157,000 square miles, the division said. A division map illustrating herd ranges shows the range of the western herd from the west coast well into the Interior, south and west of the range of the Teshekpuk herd. The division said caribou availability and abundance impact heritage and traditions of Native Alaskans in some 40 subsistence-based communities in the western portion of the state.

Four herds calve on the North Slope, including the western Arctic herd, the Teshekpuk herd, the central Arctic herd and the Porcupine herd.

The division said biologists who track the western herd are encouraged by the uptick in numbers, but not surprised.

“We’ve seen positive indicators for the past few years and have been anticipating the rebound,” said Kotzebue-based wildlife biologist Alex Hansen.

“During the declining years, adult cow mortality was high and calf recruitment was low, but since 2015 we’ve observed a positive shift in survival and recruitment rates. With fewer productive cows existing the population and an increased number of calves joining the herd things were bound to improve.”

The division said the herds have frequent cyclic highs and lows in population influenced by factors including condition of the range, weather, disease and predation. The western Arctic herd most recently peaked in 2003 at some 490,000 animals, followed by years of steady decline, the division said.

Accuracy of the 2017 photo census was improved through implementation of a newly acquired digital photography system, the division said, supporting higher flight altitudes and larger photo footprints, with improved quality allowing for more precise counting.

- KRISTEN NELSON