White paper developed at the request of the Polar Bear Ranges States.
The white paper is a product of PBRS Circumpolar Action Plan (CAP), Objective 4 - Ensure that harvest of polar bear subpopulations is managed in a biologically sustainable manner in accordance with sound conservation practices, Action HM-A6: Develop methods to collate available data from harvested bears and how to analyze that data.
Authors: Eric V. Regehr, Melissa P. Galicia, Erik M. Andersen, Fernando Ugarte, Evan S. Richardson and Amelie Roberto-Charron.
Abstract:
Harvest data are a valuable yet often underused source of information for estimating demographic parameters for polar bears (Ursus maritimus), particularly in regions where research studies are prohibitively expensive and logistically challenging. This report starts by summarizing the types of harvest-derived data that are most useful for demographic analyses, which include details of the harvest event and information on polar bear age, sex, and body condition. We then describe methods to incorporate harvest data into demographic models to increase precision and reduce bias in estimates of survival, recruitment, and population abundance, and to allow estimation of additional parameters that are relevant to management (e.g., emigration probability). We highlight analytical approaches, such as live-recapture dead-recovery models and integrated population models, that leverage harvest data for polar bears that have, and have not, previously been individually identified through research studies. We also discuss challenges to using harvest data due to nonrandom sampling, incomplete reporting, and other factors. By synthesizing current best practices, this work contributes to ongoing efforts by the Polar Bear Range States (Canada, Greenland, Norway, Russia, and the United States) to ensure sustainable management in a rapidly changing Arctic. We emphasize that obtaining accurate harvest data requires a functional harvest management regime and collaboration between researchers, managers, and the hunters and communities that collect and report harvest information.
