Salmon is a popular fish for food and sport fishing. Five species of salmon live in the North Pacific Ocean: Pink, Sockeye, Coho, Chum, and Chinook. One species, the Atlantic salmon, lives in the North Atlantic Ocean. Two other fish species that are also members of the Salmonidae fish family—steelhead and sea-run cutthroat trout—live in the Pacific Northwest. The Pacific Coast salmon populations are being threatened with extirpation from much, if not all, of their range.

At the heart of the Pacific salmon species' range, and perhaps indicative of the heart of its problems, is the Columbia River basin. Covering parts of seven states and two Canadian provinces, the Columbia River system contains over 100 dams, 56 of which are major structures, including 19 major generators of hydroelectric power. These structures present an insurmountable obstacle for these migrating fishes. Adult salmon, after growing and maturing in the ocean, return...