Moose are a prominent symbol of the Alaskan wilderness and the largest member of the deer family. They are found across a wide range, from the coastal Stikine River to the Arctic Slope’s Colville River. The species holds immense ecological significance, shaping vegetation patterns through its feeding habits. For residents, the moose is also culturally important, representing a tradition of subsistence and a source of wild protein.
The Latest Population Estimates
The total number of moose living across Alaska is a dynamic estimate based on periodic surveys. The Alaska Department of Fish and Game (ADF&G) often references a figure around 175,000 animals for the total population, representing combined estimates from various Game Management Units. This figure is a calculated approximation rather than a direct census of every individual moose. Wildlife managers use these estimates to gauge the species’ health and make informed decisions about conservation and regulated harvest.
Regional Distribution Across Alaska
Moose distribution is not uniform across Alaska, with densities varying based on habitat quality and management history. The highest concentrations are found in the Southcentral and Interior regions, where conditions favor their preferred diet. Areas like the Matanuska Valley have recorded some of the highest densities, exceeding ten moose per square mile in certain winter ranges.
Dense populations thrive along major river systems and timberline plateaus where recent disturbances have promoted favorable vegetation growth. Moose rely heavily on the abundant new growth of willow, birch, and aspen that regenerates after a wildfire or land-clearing event. For example, areas in the Interior, such as Game Management Unit 20D, saw population increases following extensive wildfires and relatively low predation rates. Conversely, populations in regions like the Kenai Peninsula can experience significant fluctuations driven by severe winter weather, which affects access to browse.
Aerial Survey Methods
Estimating the population size of moose across rugged terrain requires sophisticated techniques. The ADF&G primarily relies on aerial surveys conducted during the early winter months, when snow cover improves the contrast between the dark-colored animals and the landscape. This timing often coincides with bulls retaining their antlers, allowing biologists to determine the sex and age composition of the population.
The current standard method is a stratified random sample design, which evolved from older quadrat sampling techniques. This process involves dividing the survey area into smaller units, or quadrats, which are then categorized based on a preliminary assessment of moose density. Only a random selection of these units is then searched intensively by fixed-wing aircraft or helicopter crews.
A crucial part of this methodology is the application of a sightability correction factor (SCF). The SCF is a statistical adjustment used to account for the animals that were present but remained hidden in dense cover or missed by the observers during the count. By applying this factor to the number of moose actually observed, biologists derive a more accurate estimate of the true population size.
Factors Influencing Population Health
The numbers of moose constantly shift in response to biological and environmental forces. Predation is a major factor limiting population growth, with wolves and bears exerting significant pressure, particularly on vulnerable calves. In low-density populations, this predation can be so intense that it prevents moose numbers from recovering, a concept described as the low-density equilibrium hypothesis.
Habitat quality is another major determinant of a population’s success, directly affecting nutritional status and reproductive capacity. Wildfires and natural disturbances are beneficial because they stimulate the growth of preferred shrub species, providing high-quality winter browse. Conversely, the maturation of forests can lead to a decline in quality browse, which suppresses moose numbers.
Severe winter weather, characterized by deep snow, increases the energy expenditure required for movement and foraging, leading to reduced survival. Diseases and parasites, such as brain worm or winter ticks, can further weaken animals already stressed by poor nutrition or harsh conditions. Human activity also influences the population through regulated hunting quotas and non-harvest mortality, such as collisions with vehicles and trains.