"The Michigan Department of Natural Resources (DNR) manages the black bear (Ursus americanus) population of Michigan primarily through manipulating the harvest by adjusting the quota of hunting licenses. Estimates of the bear population play a key role in determining the appropriate license quota to achieve the DNR's bear population objectives. Past population estimates were unreliable or infrequent, so we developed a statistical catch-at-age analysis (SCAA) of the Upper Peninsula (UP) and northern Lower Peninsula (NLP) bear populations of Michigan from 1992-2015 to inform the bear management program and to allow the DNR to more closely monitor changes in the bear population over time. To support the models, we estimated the aging and sexing error rates of harvested Michigan black bears. We estimated aging error by comparing the true age of known-age bears to the age determined through cementum annuli aging techniques. Aging error rates were low (2%) at the lowest age categories and increased as bear age increased. We also estimated the sexing error rates by comparing the genetic sex of harvested bears to the sex hunters reported at the time of harvest. Sexing error was higher for females than males and differed by region. The error rates we estimated, however, were unlikely to have major effects on analyses based on sex and age data unless those data were heavily skewed toward one sex and the sexes exhibited large differences in age distribution. We also described the reproductive patterns of Michigan black bears and looked for reproductive trends over age, time and geographic region. Results showed differences between the UP and NLP. Adult females in the UP began breeding at an older age than those in the NLP and had smaller litters. By 4 years old, however, the proportion of females that bred each year was approximately 50% in each region, with only occasional major fluctuations, likely due to catastrophic mast failures. Overall, the Michigan black bear populations are as or more productive than other black bear populations in eastern North America. We developed the SCAA models for both the UP and NLP regions of Michigan to monitor the black bear population and to support the DNR's need to assess effects of past management and support decisions on future management actions. Within each region, the final selected models showed a stable to slightly increasing bear population in the UP and an increasing population in the NLP from 1992 to 2015. Model evaluation raised no major concerns of model behavior. Sensitivity analysis showed the models to be insensitive to simplifying assumptions and available data, except for the availability of mark-recapture population estimates. We recommend the DNR continue to estimate the bear populations through independent mark-recapture surveys or other means every 5 years. The SCAA models provide evidence of a stable bear population in the UP and an increasing population in the NLP. The bear populations' high annual mortality rates are offset by high fecundity."--Pages ii-iii.
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