ABSTRACT
Ballast water is considered to be one of the primary sources of aquatic invasive species (AIS). In this study, the risk of invasion was quantified for Canadian arrival ports, and this information was then used to calculate the total risk to each shipping region in Canada: the Pacific and Atlantic coasts, and the Great Lakes-St. Lawrence region. Multi-Criteria Analysis (MCA), specifically the Analytic Hiearchy Process (AHP) was used to calculate a Ballast Water Threat Index using standardized and weighted risk variables. The risk variables chosen were the vollume of ballast discharged, vessel category, percent exchange, exchange method, and voyage duration. The indices for each port were proportionally maped using ArcGIS. The Atlantic region had the highest index, followed by the Pacific and Great Lakes-St. Lawrence region. Identifying the highest - risk ports will aid decision-makers in managing the threat of ballast water in Canada by allowing prevention and treatment methods to be targeted to the appropriate ports.