Salmon
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 to the freshwater stream of their origin as they swim upstream to spawn. The adults will die shortly after this culmination of their arduous journey, and, after hatching, the young salmon—called smolts—swim downstream to the ocean to continue this life cycle.
About three-fourths of all of the population declines of salmon are directly attributable to hydroelectric dams. The dams simply do not allow a majority of these fish to successfully complete their migration, and many salmon die as they swim, or are swept, directly into the turbines. Fish ladders, stepped pools intended as an aid for fish to bypass the dams, enable some salmon to continue their journey, but many do not find their way through. As they move downstream, the smolts are slowed or stopped by the reservoirs created by the dams. Here they are exposed to larger populations of predators than in their natural riverine habitat. They are exposed to a wide variety of pathogens as well as a physical environment of warmer, slow moving waters, to which they are only moderately tolerant. Only 20% of the downstream migrants ever make it to the Pacific. Poor water quality and nutrient deficits in many stretches of the Columbia River also takes a toll on the young smolts.
Overfishing, both offshore and along the rivers, contributes to the decline of salmon populations. Fishery biologists have attempted to offset these losses of native stocks by releasing hatchery-raised salmon. However, interbreeding reduces the genetic hardiness of these fish. They also weaken the genetic lines of wild fish when they breed with them. Historically, when hatchery programs have increased the mixed stock fish population (i.e., wild and farmed) dramatically, fishing activity increases and a further depletion of wild salmon results.
To address overfishing issues, in 1996 Washington State began using a mass-marking program designed to enable fishermen to more easily identify hatchery chinook and coho salmon. Fish bred in a hatchery have their adipose fin (a small tail fin) removed before they are released. Anyone who catches a marked hatchery fish may keep it; wild salmon that are unmarked must be released back into the wild.
Realizing the need for a more balanced management plan for the Columbia River basin, Congress passed the Northwest Power Act in 1980. This act established the Northwest Power Planning Council (NWPPC), which was charged with the task of balancing long-term hydroelectric energy needs with minimizing the negative impact of dams on native salmon populations. However, despite modifications to water flow along the Snake and Columbia Rivers instituted by the NWPPC, the native salmon population continued to decline throughout the 1980s.
In 1991, the National Marine Fisheries Service (NMFS) began an extensive study of salmon populations in the northwestern United States. The NMFS found that 52 distinct populations (termed Evolutionarily Significant Units, or ESUs) of Pacific salmon have been identified in west coast states. That same year, Snake River stocks of sockeye salmon were first listed under the Endangered Species Act (ESA) as endangered. Twenty-six salmon ESUs are now listed as threatened or endangered status.
In June 2000, the NMFS adopted a rule prohibiting the killing or injuring of 14 ESUs of Pacific salmon and steelhead classified as threatened under the Endangered Species Act (ESA). This "take" rule was adopted under section 4(d) of the ESA. The rule does allow for the removal of ESA-listed salmon in association with approved programs such as scientific research and tribal fishing rights.
Various species of salmon have been added to the ESA list in the past several decades. As of May 2002, Atlantic salmon were included on the ESA with an endangered status, while chum and coho were listed as threatened. Dual status ESA species (endangered in one part of their range and threatened in another) include chinook salmon, sockeye salmon, and steelhead.
In late 2001, a U.S. district court ruled that the NMFS listing of Oregon coast coho salmon as endangered was "arbitrary and capricious" (Alsea Valley Alliance v. Evans). The court determined that excluding hatchery stock from the population assessment of this species, as NMFS had done, was inappropriate. This ruling could have far-reaching implications for other salmon stocks listed as endangered or threatened; after the Alsea ruling, six delisting petitions were filed by farming irrigation groups and other agencies requesting the removal of additional ESUs from endangered status. As of May 2002, NMFS was appealing the Alsea decision, but had also announced status reviews on fourteen endangered salmon ESUs. The Oregon coho remains on the endangered list pending the decision of the appeal.
Long-term, sustained population recovery for these ecologically, as well as economically, important salmon populations will depend on changes in both habitat and human behavior. More water is needed downstream to aid migration. This would mean less water for irrigation and for hydroelectric-generated power. Increased water flow through releases from reservoirs and spillway openings in the hydroelectric dam system has been shown to improve salmon survival rates in the Snake River. Balancing the power requirements of the Pacific Northwest with the habitat needs of salmon species will be a key part of ensuring their continued survival.
Resources
Books
Lichatowich, Jim. Salmon Without Rivers: A History of the Pacific Salmon. Washington, DC: Island Press, 2001.
Taylor, Joseph. Making Salmon: An Environmental History of the Northwest Fisheries Crisis. Seattle, WA: University of Washington Press, 2001.
Periodicals
Curtis, S. "Power Plan Trumps Salmon Recovery." Field & Stream 106, no.1 (May 2001): 16.
Gresh, Ted, J. Lichatowich, and P. Schoonmaker. "An Estimation of Historic and Current Levels of Salmon Production in the Northeast Pacific Ecosystem." Fisheries 25, no.1 (January 2000): 15–21.
Other
Northwest Fisheries Science Center, National Marine Fisheries Service. Salmonid Travel Time and Survival Related to Flow in the Columbia River Basin. March 2000 [cited May 2002]. <http://www.nwfsc.noaa.gov/pubs/ nwfscpubs.html>.
Northwest Salmon Recovery Planning. [cited May 31, 2002]. <http://research.nwfsc.noaa.gov/ cbd/trt/index.html>.
Organizations
Northwest Fisheries Science Center, NMFS, NOAA, 2725 Montlake Blvd. E, Seattle, WA USA 98112 (206) 860-3200, Email:NWFSC.Webmaster@noaa.gov, <http://www.nwfsc.noaa.gov/� 3E;
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