Simulation Modeling of the Effects of Arctic Oil Spills on the Population Dynamics of Polar Bears (AK-BRD-3)

MMS ENVIRONMENTAL STUDIES PROGRAM: ONGOING STUDIES

MMS OCS Region:			Alaska
Title:			Simulation Modeling of the Effects of Arctic Oil Spills on the Population Dynamics of Polar Bears (AK-BRD-3)
Total Cost:	$150,000				Period of Performance:	FY 1999-2001
Conducting Organization:					USGS Biological Resources Division
MMS Contact:		Chief, Alaska Environmental Studies Section
Description:
Background
In order to predict the effects of oil spills on polar bears, data on oil spill trajectories must be married with data on polar bear distributions and abundance to yield hypothetical patterns of mortality. The long-term effect of the spill on the stability of bear populations can be predicted by applying a population recovery model to mortality data as derived above. A great deal is already known about the distribution and movements of mature female polar bears in Alaska OCS Beaufort Sea planning areas through an ongoing program of satellite tagging and tracking conducted by USGS-BRD. The USGS-BRD maintains a data set on polar bear distribution in Arctic waters. Information is also available on the potential effects of oil on individual polar bears. The MMS has an updateable arctic oil-spill trajectory model that is used each time there is a Beaufort Sea Environmental Impact Statement. The study is coordinated as appropriate with MMS oil-spill modelers
Objectives
This study has been designed to link the efforts of BRD polar bear researchers and MMS oil spill modelers to predict the effects of hypothetical Beaufort Sea oil spills and other postulated mortality on the population recovery of polar bears. Computer program modules will be developed to this end. Specifically BRD researchers will: Develop/refine an independent, conceptual, polar bear population-dynamics model for Alaskan waters, with assumptions and initial conditions that can respond to hypothetical removals. Conduct a sensitivity analysis of this model. Create a database on expected mortality of polar bears under various oil spill scenarios that can be interfaced with oil spill trajectory models.
Methods
A model of polar bear population dynamics will be developed and used to simulate population-level recovery from hypothesized removals due to potential oil spills. The model will have mechanisms for linking it with the MMS Oil Spill Risk Analysis (OSRA) model trajectories for the Beaufort Sea. The final work product will include appropriate data bases, computer programs and existing algorithms on polar bear life history, population dynamics, and known seasonal distribution in Arctic waters, based primarily on existing satellite-tracking data on adult female polar bears collected by USGS-BRD. Hypothesized mortality and population recovery of both Beaufort and Bering/Chukchi Sea populations of polar bears in response to Beaufort Sea oil spills and other postulated mortality would be modeled. The interactive model, compatible with MMS hardware and software standards at the time of completion, and a user-friendly manual shall be explained and demonstrated to MMS biologists for their use in varying data input and model assumptions as appropriate for future lease sales.
Importance to MMS
Polar bears, which are hunted for subsistence, are known to be highly sensitive to direct oiling. Some subsistence hunters and environmental groups previously expressed opposition to lease sales that might adversely affect polar bears. The study will enhance MMS’s ability to predict the effects of a potential oil spill in the Beaufort Sea on large concentrations of polar bears such as those that den on Wrangel Island or that congregate near bowhead whale carcasses. The study will be beneficial in implementing the existing stipulation on protection of biological resources. The study will develop information that addresses public concerns raised during previous outreach efforts.
Current Status:
Relative probability distributions of polar bears in the Alaskan nearshore and offshore areas of the Beaufort Sea are being prepared for presentation in the final report. The projection model, including an operator’s manual for its use, will be prepared for MMS and others.
Final Report Due:				September 2003
Publications:				Two journal articles describing (1) methods and results, and (2) the population projection model will be submitted to Arctic.
Affiliated WWW Sites:				Alaska Biological Science Center
Revised date:				March 2002
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