98 REPORT OF STATE BOARD OF FISH COMMISSIONERS. 



THE PARENT-STREAM THEORY OF THE RETURN 



OF SALMON. 



By DAVID STARR JORDAN, 

 President of Leland Stanford Junior University. 



[From the Popular Science Monthly, Novemher, 1903.] 



It has been generally accepted as unquestioned, by packers and fish- 

 ermen, that the salmon of the Pacific (king salmon, red salmon, silver 

 salmon, humpback salmon, and dog salmon) all return to spawn to the 

 very stream in which they were hatched. As early as 1880, the present 

 writer placed on record his opinion that this theory was unsound. In 

 a general way, most salmon return to the parent stream, because when 

 in the sea the parent stream is the one most easily reached. The chan- 

 nels and runways which directed their course to the sea may influence 

 their return trip in the same fashion. When the salmon is mature, the 

 spawning season approaching, it seeks fresh water. Other things being 

 equal, about the same number will run each year in the same channel. 

 With all this, we find some curious facts. Certain streams will have a 

 run of exceptionally large or exceptionally small red salmon. The 

 time of the rvm bears some relation to the length of the stream: those 

 who have farthest to go start earliest. The time of running bears also 

 a relation to the temperature of the spawning grounds — where the 

 waters cool off earliest, the fish run soonest. 



The supposed evidence in favor of the parent-stream theory may be 

 considered under three heads : * ( 1 ) Distinctive runs in various streams, 

 (2) Return of marked salmon, (3) Introduction of salmon into ncAv 

 streams followed by their return. 



Under the first head it is often asserted of fishermen that they can 

 distinguish the salmon of different streams. Thus the Lynn Canal red 

 salmon are larger than those in most waters, and it is claimed that those 

 of Chilcoot Inlet are larger than those of the sister streams at Chilcat. 

 The red salmon of Red Fish Bay on Baranof Island (near Sitka) are 

 said to be much smaller than usual, and tliose of the neighboring Necker 

 Bay are not more than one third the ordinary size. Those of a small, 



*See an excellent article by H. S. Davis in the "Pacific Fisherman" for July, 1903. 



