American black bear population abundance on sovereign lands in Penobscot Nation, Maine

Abstract Hunting American black bears ( Ursus americanus ) for the Penobscot Nation, an Indigenous tribe located in Maine, USA, is a regulated process that respects both traditional customs and contemporary wildlife management practices. Each year, the Penobscot Department of Natural Resources (DNR) manages a spring bear hunt on 7 Tribal Trust properties of varying size across the state. The number of hunting permits issued is based on prior harvest data from each area, anecdotal information from hunting guides, and input from tribal members. In July 2020, the Center for Wildlife Studies began a collaborative study with the Penobscot DNR to estimate the abundance of bears in Penobscot Nation lands with the primary goal of developing a robust monitoring protocol to help set quotas for the spring bear hunt in the Penobscot Nation. From 2018–2023, we conducted noninvasive genetic sampling (NGS) in 7 study areas, from which we collected 717 black bear hair samples and identified 151 individual bears (73 F:78 M) using a new suite of genetic markers, from which we created encounter histories from 237 detection events. Our primary objectives were to 1) compare the performance of non‐spatial Huggins mark–recapture and spatially explicit capture–recapture (SECR) models within small, geographically open study areas; and 2) acquire information on survey‐design limitations and performance to inform recommendations for a robust, collaborative bear monitoring protocol throughout Maine. Across study areas, we found that preharvest Huggins abundance estimates ranged from 35 to 115 bears, whereas SECR estimates of activity centers ranged from 8 to 59 bears. Unlike with Huggins models, we were able to derive estimates for all 7 areas from SECR models, although as expected in some small study areas, the estimated numbers of activity centers were lower than the number of bears detected. Estimates from both classes of models exhibited generally modest precision; however, some were insufficiently precise to permit robust inference. Although the results from this study are valuable for informing bear management on Penobscot Tribal Lands, we caution the use of our results for setting hunting quotas. Instead, we propose a collaborative monitoring program between the Tribes and the State that relies on NGS and a robust SECR design to estimate bear demographic parameters in Maine.