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populations may in fact disrupt that important natural process. 



This is fjarticularly true for salmon. Having survived for thousands of years and 

 through radically different environments, salmon have developed some highly successful 

 reproductive characteristics (Thorpe 1986) that have fostered an exceptional degree of natural 

 hybridization: Salmon possess remarkable migratory ability and range; yet they are 

 susceptible to straying; and they will colonize new and reclaim former habitats. These 

 behaviors have allowed them to breed with numerous other populations. 



Yet NMFS seems to be saying that an ESU cannot include hybrids. If a population, 

 designated as an ESU, were to breed with another population, the federal fish agency would 

 no longer recognize it as evolutionarily significant for purposes of the act. 



Hatchery Fish and Genetic Diversity 



In addition, according to NMFS' fmal determination on Snake River Chinook, a 

 hatchery fish "should not be considered part of the evolutionarily significant unit for listing 

 purposes." Presently no hatchery fish, only populations spawning in nature, can be 

 considered of evolutionary significance. Thus, spring chinook of Rapid River Hatchery origin 

 are currently excluded from protection or use in Endangered Species Act recovery efforts 

 even though they are all that remain of the spring chinook that historically spawned in the 

 Snake River above Hells Canyon Dam. 



The federal fish agency has acknowledged, however, that, "it is important to address 

 whether any existing hatchery population can be considered part of the evolutionarily 

 significant unit, and therefore potentially be used in recovery efforts." A determination will 

 not be made until the agency issues a final decision on the role of artificial propagation in 

 carrying out the Endangered Species Act. 



NMFS scientists are worried about unwisely altering the genetic composition of fish 

 stocks. However, hatchery technologies can be used to ameliorate such risks. The act itself 

 specifically endorses conservation methods such as artificial propagation and "transplanta- 

 tion" to recover imperiled animals or plants. 



Actual experience shows that many crosses of wild and hatchery salmonids have 

 exhibited hybrid vigor. In fact, the scientific literature on breeding across various genetic 

 lines suggests that hybrid vigor--not reduced survival-is the general rule (Wohlfarth 1986). 

 When environmental conditions change, hybrids often do better than their parents. These 

 offspring have greater genetic diversity and thus have a greater potential of fitting into a 

 fluctuating environment such as the Columbia River system. 



Because, under the NMFS' definition of evolutionary significance, a species is recog- 

 nized as a group possessing unique genetic information, the goal becomes not the restoration 

 of populations to healthy, productive levels by maintaining genetic diversity and robustness, 



