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SUMMARY 1 SUMMARY The Klamath River Basin, which drains directly to the Pacific Ocean from parts of southern Oregon and northern California, contains endemic freshwater fishes and genetically distinctive stocks of anadromous fishes. Endemic freshwater fishes include the shortnose sucker (Chasmistes brevirostris) and the Lost River sucker (Deltistes luxatus). These long-lived and relatively large species, which live primarily in lakes but enter flowing waters or springs for spawning, were sufficiently abundant during the nineteenth and early twentieth centuries to support commercial fisheries. During the last half of the twentieth century, these species declined so much in abundance that they were listed in 1988 as endangered under the federal Endangered Species Act (ESA). In addition, the genetically distinctive Southern Oregon/Northern California Coast (SONCC) coho salmon (Oncorhynchus kisutch), an evolutionary significant unit (ESU) of the coho salmon, depends on the Klamath River main stem for migration and on tributary waters for spawning and growth before entering the Pacific for maturation. The Klamath Basin coho has declined substantially over the last several decades and was listed as threatened under the ESA in 1997. Factors contributing to the decline in abundance of the endangered suckers and threatened coho in the Klamath River Basin are diverse and, in some cases, incompletely documented. Factors thought to have contributed to the decline of the endangered suckers include degradation of spawning habitat, deterioration in the quality of water in Upper Klamath Lake, overexploitation by commercial and noncommercial fishing (now regulated), introduction of competitive or predaceous exotic species, blockage of migration routes, and
SUMMARY 2 entrainment of fish of all ages in water-management structures. Factors contributing to the decline of coho salmon are thought to include earlier overexploitation by fishing as well as continuing degradation of tributary habitat and reduced access to spawning areas. The threatened coho salmon also may be affected by changes in hydrologic regime, substantial warming of the main stem and tributaries, and continuing introduction of large numbers of hatchery-reared coho, which are derived only partly from native stock. The U.S. Bureau of Reclamation's (USBR) Klamath Basin Project (Klamath Project) is a system of main-stem and tributary dams and diversion structures that store and deliver water for agricultural water users in the Upper Klamath Basin under contract with the USBR. After the listing of suckers in 1988 and coho in 1997, the USBR was required to assess the potential impairment of these fishes in the Klamath River Basin by operations of the Klamath Project. In the assessments, which were completed in 2001, the USBR concluded that operations of the project would be harmful to the welfare of the listed species without specific constraints on water levels in the lakes to protect the endangered suckers and on flows in the Klamath River main stem to protect the threatened coho salmon. After release of the USBR assessment on the endangered suckers (February 2001) and following procedures required by the ESA, the U.S. Fish and Wildlife Service (USFWS) in April 2001 issued a biological opinion based on an extensive analysis of the relevant literature and field data. The biological opinion states that the endangered suckers would be in jeopardy under USBR'S proposed Klamath Project operations. The USFWS proposed a reasonable and prudent alternative (RPA) for operation of the Klamath Project. The RPA requires screening of water-management structures to prevent entrainment of suckers, adequate dam passage facilities, habitat restoration, adaptive management of water quality, interagency coordination in the development plans for operating the Klamath Project during dry years, further studies of the sucker populations, and a schedule of lake levels higher than those recommended by the USBR in its assessment. The National Marine Fisheries Service (NMFS), which assumes responsibility for the coho because it is anadromous, issued a biological opinion in April 2001 indicating that the operation of the Klamath Project as proposed by the USBR assessment of January 2001 would leave the coho population in jeopardy. The NMFS formulated an RPA incorporating reduced rates of change in flow (ramping rates) below main-stem dams to prevent stranding of coho, interagency coordination intended to optimize use of water for multiple purposes, and minimum flows in the Klamath River main stem higher than those proposed by USBR.
SUMMARY 3 During 2001, a severe drought occurred in the Klamath River Basin. The U.S. Department of the Interior (DOI) determined that the newly issued biological opinions and their RPAs must prevail; thus, water that would have gone to irrigators was directed almost entirely to attempts to maintain minimum lake levels and minimum flows as prescribed in the two RPAs. The severe economic consequences of this change in water management led DOI to request that the National Research Council (NRC) independently review the scientific and technical validity of the government's biological opinions and their RPAs. The NRC Committee on Endangered and Threatened Fishes in the Klamath River Basin was formed in response to this request. The committee was charged with filing an interim report after approximately less than 3 months of study and a final report after about 18 months of study (see statement of task, Appendix). The interim report, which is summarized here, focuses on the biological assessments of the USBR (2001) and the USFWS and NMFS biological opinions of 2001 regarding the effects of Klamath Project operations on the three listed fish species. The committee conducted a preliminary assessment of the scientific information used by the agencies and other relevant scientific information, and has considered the degree to which the biological opinions are supported by this information. During November and early December 2001, the committee studied written documentation, heard briefings from experts, and received oral and written testimony from the public, and used this information as the basis for its interim report. THE COMMITTEE'S PRINCIPAL FINDINGS The NRC committee concludes that all components of the biological opinion issued by the USFWS on the endangered suckers have substantial scientific support except for the recommendations concerning minimum water levels for Upper Klamath Lake. A substantial data-collection and analytical effort by multiple agencies, tribes, and other parties has not shown a clear connection between water level in Upper Klamath Lake and conditions that are adverse to the welfare of the suckers. Incidents of adult mortality (fish kills), for example, have not been associated with years of low water level. Also, extremes of chemical conditions considered threatening to the welfare of the fish have not coincided with years of low water level, and the highest recorded recruitment of new individuals into the adult populations occurred through reproduction in a year of low water level. Thus, the committee concludes that there is presently no sound scientific basis for recommending an operating regime for the Klamath Project that seeks to ensure lake levels
SUMMARY 4 higher on average than those occurring between 1990 and 2000. At the same time, the committee concludes that there is no scientific basis for operating the lake at mean minimum levels below the recent historical ones (1990â 2000), as would be allowed under the USBR proposal. Operations leading to lower lake levels would require acceptance of undocumented risk to the suckers. For the Klamath Basin coho, the NMFS RPA involves coordination of operations as well as reduction of ramping rates for flows below the mainstem dams and increased flows in the Klamath River main stem. Coordination and reduced ramping rates are well justified. However, the committee did not find clear scientific or technical support for increased minimum flows in the Klamath River main stem. Although the proposed higher flows are intended to increase the amount of habitat in the main stem, the increase in habitat space that can occur through adjustments in water management in dry years is small and possibly insignificant. Furthermore, tributary conditions appear to be the critical factor for this population; these conditions are not affected by operations of the Klamath Project and therefore are not addressed in the RPA. Finally, and most important, water added as necessary to sustain higher flows in the main stem during dry years would need to come from reservoirs, and this water could equal or exceed the lethal temperatures for coho salmon during the warmest months. The main stem already is excessively warm. At the same time, reduction in main-stem flows, as might occur if the USBR proposal were implemented, cannot be justified. Reduction of flows in the main stem would result in habitat conditions that are not documented, and thus present an unknown risk to the population. CONCLUSION On the basis of its interim study, the committee concludes that there is no substantial scientific foundation at this time for changing the operation of the Klamath Project to maintain higher water levels in Upper Klamath Lake for the endangered sucker populations or higher minimum flows in the Klamath River main stem for the threatened coho population. The committee concludes that the USBR proposals also are unjustified, however, because they would leave open the possibility that water levels in Upper Klamath Lake and minimum flows in the Klamath River main stem could be lower than those occurring over the past 10 years for specific kinds of climatic conditions. Thus, the committee finds no substantial scientific evidence supporting changes in the operating practices that have produced the observed levels in
SUMMARY 5 Upper Klamath Lake and the observed main-stem flows over the past 10 years. The committee's conclusions are subject to modification in the future if scientific evidence becomes available to show that alteration of flows or water levels would promote the welfare of the threatened and endangered species under consideration by the committee. The committee will make a more comprehensive and detailed assessment of the environmental requirements of the endangered suckers and threatened coho in the Klamath River Basin over the next year, during which time it will develop final conclusions.