Modeling Harvest Scenarios for the Northeastern Minnesota Moose Population
Ron Moen1
Department of Biology and Natural Resources Research Institute, University of Minnesota Duluth, Duluth, MN. U.S.A., Duluth, MN. U.S.A., US
Abstract Many North American jurisdictions at the southern edge of moose range moose have relatively small populations compared to areas like Alaska or Sweden. Some of these populations are increasing and others are declining. Many of these jurisdictions also have an annual moose harvest. The northeastern Minnesota moose population declined by over 50% from 2005 to 2012, and moose hunting was stopped in 2012. After 4 years of relative stability, which coincided with a wolf hunting season, a small tribal moose harvest was resumed in 2016. Aerial survey estimates of this moose population have averaged 3,760 ± 535 (mean ± SD) since 2014. Nineteen years of moose surveys were used to train and validate a population model to evaluate harvest and predation impacts on Minnesota moose. After calibrating the model using survey data from 2005-2025, I predicted the effect of a range of harvest scenarios on moose population size and composition from 2025 to 2035. From 40 to 80 bulls were harvested each year in a Low Harvest group and 100 to 150 bulls were harvested each year in a High Harvest group. The Low Harvest scenarios resulted in a population decline of about 250 to 450 moose relative to a No Harvest scenario by 2035. The simulated population declined by over 1,000 moose by 2035 and the bull:cow ratio declined under the High Harvest scenarios. A Low Harvest scenario would balance long-term moose population size with moose hunting traditions. I also predicted the effect of management actions that could increase the moose population by simulating a harvest of 80 bull moose each year and increasing either calf survival or adult survival until the population was stable through 2035. An increase in annual calf survival from about 23% to about 28% (only about 100 calves each year) would offset the annual harvest of 80 bull moose. Similarly, if adult survival increased by 1.5%, the population would be stable through 2035 with a harvest of 80 bull moose each year. The population model can be used to explore how harvest affects a small moose population and to inform discussions about harvest decision-making, adding management value to the annual moose survey.