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APPENDIX A. Relative Role of Other Causes of Salmon Mortality 



Salmon losses at the mainstem dams are well documented in hard 

 scientific research. Nonetheless, in what appears to be a diversionary tactic 

 in the public debate over Columbia-Snake Basin salmon recovery, various 

 commentators have pointed up other causes of salmon mortality, including 

 habitat degradation, harvest, and "ocean and /or climatic conditions." 



Habitat Degradation: Because the mainstem hydroelectric dams kill the vast 

 majority of Snake River salmon, protection and /or restoration of spawning 

 habitat alone will not save declining Snake Basin salmon stocks from 

 extinction. For example, computer projections by the Northwest Power 

 Planning Council predict negligible increases in wild salmon populations 

 from measures to protect or restore spawning grounds in central Idaho. 



The majority of salmon spawning habitat in central Idaho remains in at 

 least good condition. For example, the Frank Church River of No Return 

 Wilderness designated in 1980 — the largest wilderness area in the lower 

 48 states — protects 95 percent of the prime Middle Fork drainage of the 

 Salmon River. Nonetheless, salmon seedings in this good -to -pristine habitat 

 cu-e falling below 10 percent of carrying capacity. 



Land managers should protect pristine habitat, and restore degraded 

 spawning grounds, with particular emphasis on the control of sedimentation 

 and water temperature. These actions alone are inadequate as a salmon 

 recovery effort. 



Harvest: Similarly. b3cause the mainstem hydroelectric dams kill the vast 

 majority of Snake River salmon, severe curbs or outright bans on harvest 

 alone will not save declining fish stocks from extinction. In recent years, 

 the states and Tribes have voluntarily established lower rates and time 

 restrictions on off-shore and in-river harvest such that the National Marine 

 Fisheries Service did not identify commercisil or Tribal catch as a reason for 

 listing wild Snake River salmon stocks as threatened and endangered. For 

 at least a decade, in-river and off-shore catch on three of the four wild 

 Snake River stocks has been limited to incidental harvest. Since 1978, 

 there has been no general salmon season for Idaho anglers. 



Harvest regulators should minimize the incidental take on Snake Basin 

 salmon in mixed stock (wild and hatchery) fisheries through techniques for 

 "catch -and -release" of wild adults. Some techniques include marking all 

 hatchery juveniles, terminal fisheries, and different technologies. 



Specifically to reduce harvest impacts on fall chinook, fisheries 

 managers should set a numerical escapement goal and other stock specific 

 management objectives for the wild Snake River run. To date, regulators of 

 the fall Chinook catch have only set an escapement goal at McNary Dam on 



Drawdowns Offer Greatest Promise — Page 8 



