When Canada and the United States entered into the Pacific Salmon Treaty in 1985, a primary mutual concern was to curtail overfishing at sea to avoid depletion of salmon stocks originating in Canadian and US freshwater streams. To further the conservation of such salmon stocks, the Pacific Salmon Treaty contains provisions to encourage and reward Canada and the United States for increasing the “production” of salmon originating in their respective streams.

To increase the production of salmon, Canada and the United States often focused on artificial propagation in hatcheries rather than preserving spawning grounds and natural habitat for wild salmon. This focus on hatcheries to produce salmon coincided with a period of more intensive onstream dam building, more intensive logging of slopes adjacent to and upland of salmon spawning grounds, and more intensive diversion of water out-of-stream for farms and cities that reduced instream flow. The artificially propagated salmon from hatcheries were intended to replace the wild salmon runs displaced because of habitat loss due to dams, logging, and diversions.