ADFG Hopes Predator Control Process Will Help Decreased Mulchatna Caribou Herd Numbers

Photo by Zak Richter/NPS

The press release is courtesy of the Alaska Department of Fish and Game:

ADF&G concludes predator control for the year to benefit Mulchatna Caribou

(Dillingham) – In March 2023 the Alaska Board of Game approved and directed the Department to implement a revised Intensive Management Program to increase abundance of the Mulchatna Caribou Herd, which has been closed to hunting since fall 2021. This herd peaked at approximately 200,000 animals in 1997 and then declined to just over 12,000 (~96% decline) by 2017 and remained at that level since then. During the peak, this herd provided up to 4,770 caribou for local communities, and resident and nonresident hunters. Recognizing that there are 48 communities within the traditional range of this once expansive herd, the public requested that the department and board work to rebuild the herd and restore this source of food.

Caribou survival can be affected by disease, predation, harvest, and animal nutrition. The Board of Game reasoned that addressing predation is something that can be addressed now. Wolf control by the public, using aerial methods authorized by the Board of Game, has been active during winter since 2012. Even as approved areas for wolf control have expanded, the herd size decreased to its current low level and calf summer survival has been poor. Both bears and wolves have been identified by research as important factors causing low calf survival and potentially limiting the ability of the herd to increase. The board revised the existing wolf control program to include bears and wolves specifically on the caribou calving grounds. Reducing the number of bears and wolves was a logical step in adaptive management to determine if summer calf survival can be improved. While there are other factors to consider with the herds’ decline (e.g., habitat capability, disease), predator control is an immediate tool the department can use to attempt to reverse the herds’ decline. The spring portion of this Intensive Management effort was accomplished by department staff. The objective was to have experienced staff locate and take predators within an area defined as the calving grounds of the western subgroup. This control program is specifically designed as an effort to enhance calf survival. The program has not expanded outside the western calving ground. Predator reduction activities were conducted on state land only.

Staff spent 17 days between May 10 and June 4 following caribou and searching for evidence of predation (caribou fleeing or predators actively chasing or eating caribou). All bears and wolves located in this search were killed and hides and skulls were salvaged when safe to do so. Meat from all black bears and some brown bears was transported to local villages and provided for subsistence. A total of 94 brown bears, 5 black bears, and 5 wolves have been removed. The program has concluded for the season.

The Division of Wildlife Conservation will monitor calf summer survival to see if it increased in the treatment area as intended and whether the associated groups show signs of increased abundance during the post- calving aggregations compared to recent years and compared to the untreated eastern calving groups. This information will be evaluated to determine if further bear and wolf reductions during spring calving is warranted to aid further improvement in calf survival and herd growth.

The Department does not have population concerns for these removals of bears and wolves. Bear and wolf populations are healthy in western Alaska. The removals of wolves and bears in the western spring calving control area are occurring in a relatively small area that is surrounded by healthy, intact habitat in State and Federal lands where control activities are not occurring. Those areas are refugia from the spring control activities for predator populations. Based on prior research, full recovery to pre-treatment levels is expected within a few years once the reduction activities have been completed, which is anticipated to occur from a combination immigration of predators into the area and reproduction.

As noted above, the Mulchatna caribou herd has historically provided food for 48 communities in the region and other interested hunters. The control program was undertaken in an effort to provide a secure food resource for Alaskans.