Natural phenomena—predators, droughts, floods, and fluctuating oceanic conditions—stress salmonids and contribute to the variable abundance of their populations. Currently, 28 distinct population segments of five salmonid species have been listed as either endangered or threatened under the Endangered Species Act (ESA, see Table 1 ), with three additional populations identified as "species of concern." While no species of anadromous trout or salmon is in danger of near-term extinction, individual distinct population segments (designated as "evolutionarily significant units" or ESUs) within these species have declined substantially or have even been extirpated. The American Fisheries Society considers at least 214 Pacific Coast anadromous fish populations to be "at risk," while at least 106 other historically abundant populations have already become extinct. Human activities—logging, grazing, mining, agriculture, urban development, and consumptive water use—can degrade aquatic habitat. Silt can cover streambed gravel, smothering eggs. Poorly constructed roads often increase siltation in streams where adult salmon spawn and young salmon rear. Removal of streamside trees and shade frequently leads to higher water temperatures. Grazing cattle remove streamside vegetation and exacerbate streambank erosion. Urbanization typically brings stream channelization and filled wetlands, altering food supplies and nursery habitat. Habitat alterations can lead to increased salmonid predation by marine mammals, birds, and other fish. Dams for hydropower, flood control, and irrigation substantially alter aquatic habitat and can have significant impacts on anadromous fish. Protection and Restoration Efforts

The National Marine Fisheries Service (NMFS, also popularly referred to as "NOAA Fisheries") in the National Oceanic and Atmospheric Administration, Department of Commerce, implements the ESA for anadromous salmonids. When a federal activity may harm an ESA-listed salmonid, the ESA requires the federal agency to consult with NMFS to determine whether the activity is likely to jeopardize the survival and recovery of the species or adversely modify its critical habitat. In the Columbia River Basin, the Northwest Power and Conservation Council took the lead under the 1980 Pacific Northwest Electric Power Planning and Conservation Act ( P.L. 96-501 ), by attempting to protect salmon and their habitat while also providing inexpensive electric power to the region. Although federal agencies and public utilities have spent hundreds of millions of dollars on technical improvements for dams, habitat enhancement, and water purchases to improve salmon survival, some populations have continued to decline. Recent years have seen an increased interest by state governments and tribal councils in developing comprehensive salmon management efforts.
Along the Pacific Coast, 28 distinct population segments of Pacific salmon and steelhead trout are listed as either endangered or threatened under the Endangered Species Act (ESA), with three additional populations identified as "species of concern." While no species of anadromous trout or salmon is in danger of near-term extinction, individual population segments within these species have declined substantially or have even been extirpated. The American Fisheries Society considers at least 214 Pacific Coast anadromous fish populations to be "at risk," while at least 106 other historically abundant populations have already become extinct.
Human activities—logging, grazing, mining, agriculture, urban development, and consumptive water use—can degrade aquatic habitat. Silt can cover streambed gravel, smothering fish eggs. Poorly constructed roads often increase siltation in streams where adult salmon spawn and young salmon rear. Removal of streamside trees and shade frequently leads to higher water temperatures. Grazing cattle remove streamside vegetation and exacerbate streambank erosion. Urbanization typically brings stream channelization and filled wetlands, altering food supplies and nursery habitat. Habitat alterations can lead to increased salmonid predation by marine mammals, birds, and other fish. Dams for hydropower, flood control, and irrigation substantially alter aquatic habitat and can have significant impacts on anadromous fish. In addition, natural phenomena stress fish populations and contribute to their variable abundance.
Current management efforts aim to restore the abundance of ESA-listed native northeast Pacific salmonids to historic, sustainable population levels. The National Marine Fisheries Service (NMFS, also popularly referred to as "NOAA Fisheries") in the Department of Commerce implements the ESA for anadromous salmonids. When a federal activity may harm an ESA-listed salmonid, the ESA requires the federal agency to consult with NMFS to determine whether the activity is likely to jeopardize the survival and recovery of the species or adversely modify its critical habitat.
Prior to the listing of salmonid "evolutionarily significant units" (ESUs) under the ESA, the Northwest Power and Conservation Council took the lead in the Columbia River Basin under the 1980 Pacific Northwest Electric Power Planning and Conservation Act, by attempting to protect salmon and their habitat while also providing inexpensive electric power to the region. Under this effort, federal agencies and public utilities have spent hundreds of millions of dollars on technical improvements for dams, habitat enhancement, and water purchases to improve salmon survival. Recent years have seen an increased interest by state governments and tribal councils in developing comprehensive salmon management efforts.
This report summarizes the reasons for ESA listings and outlines efforts to protect ESA-listed species.