74 



THE MIGRATION AND CONSERVATION OP SALMON 



homing of these salmon is of a sufficient 

 degree to justify conservation measures on 

 the basis of the parent stream principle." 

 The differences of opinions come as to the 

 factors involved in the precision with which 

 the salmon do return to the parent stream 

 and as to the factors which bring about 

 straying. 



The author will defend his thesis that 

 the guiding factors are the physical and 

 chemical characteristics of the water to 

 which salmon are sensitive and do react 

 and by so doing do reach the spawning 

 grounds, the parent stream. In mammals 

 it has been shown by brilliant, unique, in- 

 genious experimentation, that receptors de- 

 veloped from structures associated with 

 branchial arches are sensitive to carbon 

 dioxide tension, chemicals and low oxygen 

 (anoxia). No doubt it is this response to 

 low oxygen that keeps fishes out of the 

 oxygenless hypolimnion of lakes. Marine 

 fishes including salmon ( Shelf ord and 

 Powers, 1915) do make directive responses 

 to gradients of carbon dioxide tension and 

 of fresh-salt water mixtures. For a more 

 intelligent discussion of the subject, the 

 behavior of the salmon during their migra- 

 tory movements should be known as well 

 as the physical and chemical characteristics 

 of the water through which they are mov- 

 ing. Unfortunately, little attention has 

 been given to either. The author has ob- 

 tained information from reliable sources on 

 certain facts concerning the behavior of the 

 red or sockeye (0. nerka) and of the king 

 or spring (0. tschawytscha) salmon. The 

 king salmon migrates at deeper levels both 

 in the salt water and in the rivers. The 

 reds are often seen "finning." The king 

 does not fin and it keeps in the deeper chan- 

 nels of the river. In the Columbia River 

 the king salmon migrates in the deeper and 

 faster water while the red salmon tends to 

 follow closer to the banks in the less fast 

 and the shallower areas. The fishermen fish 

 for and catch king salmon at greater 

 depths. Some have been caught as deep 

 as 90 fathoms. 



In a personal communication to the 

 author Mr. George B. Kelez states as fal- 

 lows: 



The following notes are some observations on the 

 vertical distribution and jumping habits of vari- 

 ous species of adult salmon while in the [Puget] 

 Sound and other open waters, and while migrating 

 upstream in large rivers. 



These notes do not include observations of 

 salmon while in shallow spawning bed streams, nor 

 do they include fish which have met with obstruc- 

 tions, extremely fast water or rapids. The writer 

 does not feel these observations applicable to this 

 discussion, since under such conditions the fish do 

 not have normal freedom of movement. 



Open water observations, made on the fishing 

 grounds, include the Puget Sound, Alaska Penin- 

 sula and Bristol Bay areas. Stream observations 

 were made on the Kvichak, Naknek and Egegik 

 Rivers of the Bristol Bay area. 



Red Salmon (0. nerica) 



Open Waters: 



Red salmon apparently do not range deeply into 

 the water but stay near the surface. Fishermen 

 find this species can be caught nearer the shore 

 than other species inhabiting the same area. The 

 writer has on several occasions observed small 

 schools swimming not more than three feet under 

 the surface. When found ' ' gilled ' ' in the mesh 

 of a purse-seine "lead," these fish tend to go up 

 near the cork line. 



Red salmon do not commonly jump in open 

 waters, more frequently they break water with 

 snout and dorsal fin. Among fishermen this expo- 

 sure is known as ' ' finning. ' ' Next to king salmon, 

 reds expose themselves less than other species of 

 salmon. 



Upstream: 



Here this species tends to keep to the upper three 

 feet of water; they do a small amount of jump- 

 ing; more frequently they "fin." 



King Salmon (0. tschawytscha) 



Open Waters: 



King salmon are caught by commercial trollers, 

 fishing at a depth of 30 to 40 fathoms or even 

 deeper. To the writer's knowledge, this species 

 has not been observed swimming near the surface. 

 It is rare to see this species jump. »• 



Upstream: 



Kings were observed swimming deeper than reds 

 or chums in the same area. They were neither ob- 

 served jumping nor "finning. "i 



1 The information concerning the behavior of 

 the salmon was obtained through the kindness of 

 Dr. F. A. Davidson, Director, Seattle, Washington, 

 Bureau of Fisheries; Mr. George R. Kelez, Acting 

 Director, Seattle, Washington, Bureau of Fisheries, 

 and Mr. Richard T. Smith of the Washington 

 State Fisheries Department. Mr. Kelez was for 

 some years engaged on a red salmon research prob- 

 lem on the Chigniti river and lakes, Alaska. Mr. 

 Smith has had first hand information in fishing. 



