PACIFIC SALMON 



49 



have gone such great distances at sea that 

 they would seem to be beyond any possible 

 hydrographic influence that their home 

 streams might have. If this is true of the 

 Columbia River Chinooks and the Bristol 

 Bay red salmon it seems reasonably certain 

 that it is a pattern of behavior generally 

 common to the Pacific salmon. 



As a matter of practical conservation it is 

 obviously of importance to the troll fisher- 

 men of southeastern Alaska and of British 

 Columbia that the Columbia River Chinook 

 salmon runs be conserved; and it is of im- 

 portance to those who are interested in the 

 conservation of the Columbia River salmon 

 to know what is happening on the distant 

 fishing grounds lest the developments there 

 negative the influence of any conservation 

 measures that may be effected in the Colum- 

 bia River itself. Not that, at present, any- 

 thing is likely to be done about it ; but per- 

 haps, in the fullness of time, some wise legis- 

 lator will decide that something ought to be 

 done. If that should happen he will likely 

 turn to some biologist and expect an imme- 

 diate answer to his question as to what ought 

 to be done. Which reflection, however, is 

 beside the point. 



My primary interest in this subject is, 

 obviously, that of the practical fishery con- 

 servationist, and I suppose that I am in- 

 clined to be somewhat impatient with theo- 

 ries and attitudes that I fear may provide 

 ammunition to those opposed, for one reason 

 or another, to true conservation. The entire 

 program for the conservation of the salmon 

 of the Pacific coast and Alaska, so far as it 

 depends from scientific information and not 

 from political exigencies, is based upon the 

 acceptance of the ''home stream theory" — 

 in other words, of the theory that the several 

 species each consists of a large number of 

 independent local populations or races and 

 that the adults return from the ocean pre- 

 dominantly to the streams of their nativity. 

 I feel that this theory is on solid ground and 

 must be accepted as fundamental. The 

 practical conservationist must assume, in the 

 absence of any conflicting evidence, that the 

 Pacific salmon do return to their home 

 streams from whatever distance they may go 



at sea; he must determine the drain upon 

 the salmon runs by fisheries at such distant 

 points as may prove to be in the path of the 

 migration and he must apply his conserva- 

 tion measures throughout the range of the 

 populations in question to the end that each 

 may be maintained at the most productive 

 level. 



Summary 



1. A rational conservation program for 

 such migratory fishes as the salmon must be 

 based on a knowledge of (a) whether or not 

 the species consists of local, self-perpetua- 

 ting populations and (b) the nature and 

 extent of the oceanic migrations. 



2. The conservation of a species that is 

 broken up into local self-perpetuating popu- 

 lations involves the determination of the 

 causes of mortality at all stages in the life- 

 history of each group. 



3. Species that are not so broken up may 

 be conserved by measures of more general 

 application. 



4. In the case of migrating species the 

 routes traversed by the individuals of each 

 population group must be known in order 

 that the causes of mortality may be deter- 

 mined and that appropriate conservation 

 measures may be applied. 



5. In the case of the Pacific salmon, the 

 evidence shows clearly the existence of local, 

 self-perpetuating populations. 



6. The evidence also shows clearly that the 

 Pacific salmon return from their life in the 

 sea predominantly to their home streams 

 thus justifying acceptance of what is known 

 as the "home stream theory." 



7. It has also been shown that many of 

 the Pacific salmon travel hundreds of miles 

 in the ocean, by the nearest route, from 

 places where they have been captured and 

 tagged, before they enter streams for the 

 purpose of spawning. 



8. In the absence of any conflicting evi- 

 dence it is believed that the "home stream 

 theory " applies to these fish that travel long 

 distances in the ocean as well as to those that 

 may not travel so far and that the basing of 

 practical conservation measures upon an ac- 



