Managing Chronic Wasting Disease in Deer Using a Split Hunting Season Structure

Abstract

Chronic Wasting Disease (CWD) is a slow-moving, always fatal prion disease of cervids. Management of CWD focuses on several strategies including removal of those animals with a greater probability of infection. Among deer in Montana, bucks of both species have higher prevalence. CWD was first documented in north-central Montana in mule deer (Odocoileus hemionus) in 2017 and in white-tailed deer (Odocoileus virginianus) in 2018. In 2020, a split deer season, three weeks of a general deer season followed by two weeks of limited antlered buck permits, was implemented in four hunting districts in an effort to maintain low prevalence rates and reduce the potential for spread of the disease. Permit quotas were adjusted with the intent that permit harvest comprised 10 percent of the total buck harvest. For the five seasons since implementation, permit success averaged 53% and 47% for buck mule deer and buck white-tailed deer respectively. For the same period, permit harvest averaged 12% of the total buck mule deer harvest and 8% of the buck white-tailed deer harvest. Observed three-year CWD prevalence ranges from 0.06 to 0.03 for mule deer and 0.08 to 0.00 for white-tailed deer. Permit quotas have been increased where prevalence is above 0.05 for the 2025 season. Of those permit holders with an opinion, 76% approve or strongly approve of the season structure.