Pacific salmon are the paramount cultural and spiritual symbol of the Pacific Northwest. Since the beginning of human habitation, salmon have been central to subsistence, trade, and even religion. The natives of the region considered salmon so crucial to their way of life that they bargained in 1850s treaties to continue to harvest a share of the salmon runs in return for ceding to the United States the lands that now forms the states of Idaho, Oregon, and Washington. A century and a half later, because of their environmental sensitivity, Pacific salmon runs from California to Alaska function...