Increasing Vessel Traffic in the Bering Strait: How an Agent Based Model Can Aid in Understanding Wildlife Impacts

Decreases in summer Arctic sea ice extent and increases in shipping technology have supported increases in Arctic maritime traffic, and raised the status of Bering Strait as an increasingly critical international shipping waterway. The US National Park Service is attempting to address community and local concerns associated with the increasing international shipping through the Bering Sea into the Arctic. A key component of this research was the development of a shipping simulation model that allowed a better understanding of shipping volumes and densities over a year’s time and project current shipping volumes into 2025. The agent based simulation was based on the US Committee on Marine Transportation projections to the year 2025. Following the model development, and verification, a sound component was added to the model to assess the potential of using the model to understand the potential sound increase associated with vessel traffic increase. In this model noise from vessels spread while traveling within a 100 x 100 km grid cell using a simple frequency-dependent geometric spreading function (from Pine et al. 2014).Equivalent continuous sound levels (Leq) are then used to calculate Leq levels within a cell on a weekly basis throughout the year. Results of the model provided a detailed examination of monthly shipping volumes across the Bering Sea in the form of maps that can then be compared against seasonal wildlife habitat maps to gain an understanding of risks to wildlife. This model represents an attempt to tie vessel sound to traffic projections in an area of the world with an increasing degree of vessel traffic where only limited local traffic previously existed.