Sites across the Great Lakes Basin are assessed to identify and prioritize the most likely points of introduction for new AIS.
- The size of the Great Lakes Basin presents a challenge for implementing comprehensive early detection for aquatic invasive species.
- Sites across the Great Lakes Basin are assessed to determine if they are a likely location for AIS introductions based on several risk factors.
- A regional framework for Great Lakes early detection provides a tool to identify priority sites for AIS early detection efforts across the Basin.
The Great Lakes present unique challenges to early detection efforts, with a surface water area of 95,000 square miles (245,759 square km) and shoreline length of 10,210 miles (17,017 km). To best target early detection efforts across such a large area, sites with the highest risk of new introductions, including movement of species established elsewhere in the Great Lakes Basin, are identified and prioritized.
A systematic method for identifying, evaluating and prioritizing early detection sites was developed as part of the Aquatic Invasive Species Interstate Surveillance Framework for the U.S. Waters of the Great Lakes (the Framework). The method is based on the likelihood that a watch list species could be introduced by any of the key pathways of spread (e.g., shipping, recreational boating, and organisms in trade). To evaluate and prioritize individual locations, the U.S. waters of the Great Lakes and their tributaries were divided into 5,953 standardized units (or “sites”). Analysis of key risk factors found that about 1,800 sites have invasion risk scores greater than zero. The method categorizes high-risk, priority sites for different groups of species: fish, invertebrates, and plants. A comparable site-prioritization system is under construction for Canada.
(For more information see Site Prioritization Methods.)