48 



Fish Populations 



In this century fish populations of the Pacific Northwest have been profoundly diminished 

 along with much of the regions unique character (Eley and Watkins 1991). More than 

 200 distinct stocks (genetically distinct fish populations native to a particular drainage 

 system; Bisson et al. 1992) of anadromous salmon in the western United States are 

 presently at risk of becoming extinct (Nehlsen et al. 1991). Of the Pacific salmon, 

 steelhead, and sea-run cutthroat trout once common in the states of the Pacific Coast. 

 106 are extinct, 102 are endangered, 58 are at moderate risk, and 54 are a matter of 

 concem (Nehlsen et al. 1991). For example, populations of naturally spawning salmonids 

 in the Columbia River have declined by more than 95%. This precipitous decline in 

 salmon populations is indicative of the progressive degradation of our region's 

 watersheds. 



Habitat destruction, overfishing, and harmful interbreeding of wild and hatchery fish have 

 been implicated in the observed declines of Pacific Northwest salmon stock abundance 

 (Nehlsen 1991, Bisson et al. 1992). Existing fish culture practices have resulted in an 

 overall loss of genetic diversity among wild fish populations (Bisson et al. 1992, Allendorf 

 et al. 1987). State fish hatcheries' programs address the symptoms of the decline of 

 salmon populations, but do not address the real problems of overharvest and habitat 

 degradation (Meffe 1992). Furthermore, hatchery fish are being released into degraded 

 riverine systems that are largely unsuitable for survival, reproduction, or migration (Meffe 

 1992). In final analysis, the future of the Pacific salmon depends upon the preservation 

 and restoration of its wild populations and their habitats through management based on 

 an ecosystem perspective (Frissell 1992, Maclean and Evans 1981 , Nehlsen et al. 1991). 



II Fundamental Elements of Ecologically Healthy Watersheds and Fish 

 Habitat in the Pacific Northwest 



Four fundamental components comprise ecologically healthy watersheds in the Pacific 

 Northwest (Naiman et al. 1992). These are: 1) basin geomorphology as it relates to 

 natural disturbance regimes, 2) hydrologic patterns, 3) riparian forests, and 4) diverse and 

 abundant habitat. 



Basin Geomorphology 



Basin geomorphology (landform development in river drainage basins) in ecologically 

 healthy watersheds is detemriined by the type, frequency, and intensity of natural 

 disturbances. Recent studies in the Pacific Northwest have shown that the delivery and 

 routing of water, sediment, and woody debris to streams are the key processes regulating 

 the vitality of watersheds and their drainage networks (Naiman et al. 1992). The natural 

 occun-ence of these disturbances is essential to the health of the watershed. For 



