| Summary: | All seven species of Pacific salmon on both sides of the North Pacific have declined significantly from historic levels, but not as dramatically as have Atlantic salmon. Hatchery production has been used to maintain some runs in the southern region of the range (e.g., Japan, Korea, California, Oregon, and Washington). In California, Oregon, Washington, Idaho, and southern British Columbia, runs have been depleted by past over-fishing, dam construction and operation, water withdrawal for irrigation and industrial cooling, competition with hatchery-produced salmon, competition with various non-indigenous fish species, predation by marine mammals and birds, and climatic and oceanic shifts. Runs in the northern half of the range (e.g., Russian Far East, Alaska, Yukon, and northern British Columbia) are in much better condition. The northern runs have been abundant for the past several decades, but will likely decline somewhat for several decades because ocean conditions in the North Pacific tend to shift on such a several-decade time cycle. In the western region of the contiguous United States, billions of dollars have been spent in a so-far failed attempt to reverse the long-term decline of wild Pacific salmon. Of the Earth's four regions (i.e., Asian Far East, Atlantic Europe, eastern North America, and western North America) where salmon runs occurred originally, it appears probable that western North America will emulate the other three: extirpated or much reduced runs in the southern half of the range; runs closer to historic levels in the northern half of the range (British Columbia northward).
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