The aquatic ecosystem classification (AEC) is a science-based tool that groups and classifies Ontario’s rivers and streams based on their: * physical attributes, such as water temperature * watershed characteristics, such as upstream drainage area The Ministry of Natural Resources and Forestry (MNRF) is responsible for sustainably managing and deriving economic benefit from the fisheries and water resources in the 490,000 km of Ontario’s rivers and streams. The AEC reduces the complexity of these vast aquatic networks using consistent and quantitative methods to build a standardized data foundation that helps MNRF staff with landscape level planning and policy development.