The Hatchery Scientific Review Group (HSRG) determined that in order to understand if and how hatcheries might contribute to goals for conservation and harvest, hatcheries must be viewed in their evolutionary and ecological context. Watersheds differ from one another as habitats both for fish and for people. The benefits and risks that derive from hatchery programs are different among watersheds and therefore hatcheries must be viewed in a watershed/regional context. However, salmon and steelhead also range far from the streams where they are spawned and are therefore also part of the ecosystem on a very broad geographic scale.
Taking these facts into account, the HSRG divided the Puget Sound/Coastal Washington area into ten regions, and the Columbia River Basin into 14 regions, and conducted its review of hatcheries at that level.