662 
BULLETIN OF THE BUREAU OF FISHERIES 
This constant increase in the catch of this species has been due undoubtedly to a corre- 
sponding increase in the amount of trolling, in which type of fis hi ng kings and cohos 
are taken almost exclusively. It has been mentioned above (p. 575) that tagging 
experiments have shown that many of the kings taken by troll off the coast of south- 
eastern Alaska and British Columbia are native to the Columbia River and to a 
lesser extent to the rivers farther south. It is impossible to say to what extent local 
races enter into the catch, but there can be little doubt that the southern fish, par- 
ticularly those of the Columbia River, form an important element in the catch and 
have made possible this constant increase. Under such conditions the conservation 
of this species in southeastern Alaska is not at all a local matter, but is intimately 
involved with the troll fishery off the coasts of British Columbia, Washington, Oregon, 
and California, as well as the important fisheries in the Columbia River. 
The Columbia is undoubtedly the most productive stream in the world so far as 
king or chinook salmon are concerned and evidently do min ates the catch throughout 
at least the northern part of the western coast. The Columbia River runs have been 
fished intensively for many decades and show unmistakable signs of depletion in spite 
of artificial propagation which is probably unparalleled in extent and efficiency ; the 
spawning areas have been greatly reduced by the erection of dams and the drain on 
the resources has been gradually increased by the development of the fishery in the 
river and more recently by the increase in trolling. The future seems doubtful and 
a continuation of the increase in the catch of kings in southeastern Alaska seems most 
unlikely, although certainly there is no indication of reduced catches in the data 
herein considered. If this valuable fishery resource is to be preserved, however, a 
complete and detailed study of all the influences that bear upon the maintenance of 
the Columbia River kings should be undertaken without delay. 
