Upstream Salmon and Society in the Pacific Northwest (1996) / Chapter Skim
Currently Skimming:
1 Introduction
1 Introduction
Pages 18-27
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From page 18... ...
Before European and American explorers and settlers arrived in the Pacific Northwest of North America in the nineteenth century, salmon were so abundant there that an American Indian economy had been founded on them; yet human exploitation rates and disturbances of the fishes' environment were small enough that the salmon populations did not diminish over the long run. Wild salmon, which once numbered more than 8-10 million returning adults in the Columbia River basin alone, have declined to less than one-tenth that number up and down the coast of the Pacific Northwest.
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From page 19... ...
In response to concern over the continuing decline of salmon stocks in the Pacific Northwest and the controversies about how to arrest or reverse the decline, Congress requested advice from the National Research Council (Senate Report 102-106, Appropriations Bill for Departments of Commerce, Justice, and State, the Judiciary, and Related Agencies, 19923. The National Research Council thereupon established the Committee on Protection and Management of Pacific Northwest Anadromous Salmon to evaluate information on the status of various stocks in the Pacific Northwest, identify causes of their decline, and suggest a comprehensive approach to protecting and managing them (the complete charge to the committee is in Appendix A)
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From page 20... ...
The homing habit results in local populations being adapted to particular streams: The genetic distinctions of local populations, or demos, make the genetic structure of salmon complex and different from that of most fish species. Chapter 2 contains more information on the biology and ecology of the Pacific salmon and Chapter 4 discusses the status of wild salmon populations, including difficulties in evaluation of status.
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From page 21... ...
Evolutionary, Genetic, Ecological, and Spatial Units of Concern Pacific salmon are widely distributed and occur in diverse habitats; they are correspondingly biologically diverse. Each species is divided genetically and evolutionarily into subspecies (races)
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From page 22... ...
Source: NMFS 1995. gered Species Act protects not only species but, for vertebrates, "subspecies, varieties, and distinct population segments." However, the act does not define "distinct population segments." It would be important to understand what levels of evolutionary (or taxonomic)
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From page 23... ...
Biological relationships of salmon to freshwater are well known because a river has an easily studied upland watershed and a lake has a clear shoreline and is without abyssal depths. Considerably less is known about the vast and widely dispersed ocean habitats of salmon.
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From page 24... ...
The salmon production cycle has three principal components that determine abundance: reproductive potential of adults returning from the sea to spawn, which is affected by their growth at sea; production of offspring from natural reproduction in streams and artificial propagation in hatcheries; and sources of mortality (including natural mortality, fishing mortality, dam-caused mortality, mortality from habitat alterations and changes in environmental conditions, and so on)
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From page 25... ...
Part of the need to articulate and discuss diverse goals and values is practical: actions undertaken without clear articulation of goals are unlikely to achieve anything useful. Consideration of goals and values has been essential to this committee in addressing how to approach the salmon problem, and has led it to frame its conclusions and recommendations in terms of rehabilitation of salmon stocks a pragmatic approach to improving the situation that relies on natural regenerative processes in the long term and the selected use of technology and human effort in the short term-rather than on attempts to restore the ecosystem to some pristine former state and rather than on a primary reliance on substitution, i.e., the use of technologies and energy inputs, such as hatcheries, artificial transportation, and modification of stream channels.
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From page 26... ...
Examples of substitution could include production hatcheries, barging of young salmon around dams, construction of fish ladders and stream channels, altering instream flow by drawdown or changing storage, and other activities that can reasonably be expected to require continuing human input. Substituting for natural processes to maintain salmon runs is possible in at least some portions of most streams, but it would be expensive, and the cost in human and financial resources is expected to increase rather than to decrease or stabilize in the future.
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From page 27... ...
Rehabilitation would protect what remains in an ecosystem context and regenerate natural processes where cost-effective opportunities exist. It might be necessary to use the technologies and techniques suggested in the preceding paragraph to maintain the essential ecosystem components in the short term, but the ultimate goal is to modify (i.e., rehabilitate)
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