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Artificial Propagation
There are several artificial propagation programs for salmon production within the
Columbia River Basin. These programs were instituted under federal law to lessen the
effects of lost natural salmon production within the basin from the dams. The hatcheries
are operated by federal, state, and tribal managers. For more than 100 years, hatcheries
in the Pacific Northwest have been used to produce fish for harvest and replace natural
production lost to dam construction. Hatcheries have only minimally been used to
protect and rebuild naturally produced salmonid population (e.g., Redfish Lake sockeye
salmon). In 1987, 95% of the coho salmon, 70% of the spring Chinook salmon, 80% of
the summer Chinook salmon, 50% of the fall-run Chinook salmon, and 70% of the
steelhead returning to the Columbia River Basin originated in hatcheries (CBFWA 1990).
More recent estimates suggest that almost half of the total number of smolts produced in
the basin come from hatcheries (Beechie, Liermann et al. 2005).
The impact of artificial propagation on the total production of Pacific salmon and
steelhead has been extensive (Hard, Jones et al. 1992). Hatchery practices, among other
factors, are a contributing factor to the 90% reduction in natural coho salmon runs in the
lower Columbia River over the past 30 years (Flagg, Waknitz et al. 1995). Past hatchery
and stocking practices have resulted in the transplantation of salmon and steelhead from
non-native basins. The impacts of these hatchery practices are largely unknown.
Adverse effects of these practices likely included: loss of genetic variability within and
among populations (Busack 1990; Riggs 1990; Hard, Jones et al. 1992; Reisenbichler
1997), disease transfer, increased competition for food, habitat, or mates, increased
predation, altered migration, and the displacement of natural fish (Steward and Bjornn
1990; Hard, Jones et al. 1992; Fresh 1997). Species with extended freshwater residence
may face higher risk of domestication, predation, or altered migration than species that
spend only a brief time in freshwater (Hard, Jones et al. 1992). Nonetheless, artificial
propagation may also contribute to the conservation of listed salmon and steelhead.
However, it is unclear whether or how much artificial propagation during the recovery
process will compromise the distinctiveness of natural populations (Hard, Jones et al.
1992).
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