15 



NOTES ON THE MOVEMENTS OF THE YOUNG OF THE 

 STEELHEAD TROUT (Salmo gairdneri, Richardson) 



IN MARIN COUNTY STREAMS. 



By N. B. SCHOFIELD, of California Fish Commission. 



The steelheads ascend Paper Mill Creek and its tributaries regularly 

 each year for the purpose of spawning. Late in October and early in 

 November they appear in tide water, where they remain until the first 

 good rains. They then ascend the creeks, and spawn on the gravel 

 bars in December and January, reaching their height in early January. 



After spawning the steelheads drop back down the stream, and remain 

 for some time in the holes in tide water before running into salt water. 

 Unlike the salmon, they do not die after spawning, but drop back into 

 salt water and return to spawn again. Steelheads from the lower Paper 

 Mill Creek examined in April after spawning showed the ovaries with 

 the eggs forming, which would probably have matured by the next 

 winter run. 



The first young steelheads appear in shallow water along the edges of 

 the stream after absorbing their yolk sacs late in March, but they do not 

 appear in any great number until late in April. In 1897 they began to 

 show themselves in considerable numbers by the 15th of April, and by 

 the 25th the edges of the stream in places were fairly black with them. 

 At this time they are not very shy and are not frightened when one 

 comes near them, unless his shadow chances to fall on them. By being 

 cautious one can with his hand scoop them out onto the bank. This 

 cannot be done with the young salmon of the same age, as they are 

 much more shy. These young steelheads as they lie in the shallow water 

 kept their heads against the current, and were entirely absorbed with 

 the task of catching something to eat feeding in the same way as has 

 been described in the case of the young Quinnat salmon. In a very few 

 days they left the shallow water and moved more into the center of the 

 stream, where there is more floating particles of food for them to catch. 



By the middle of May nearly all the small steelheads had moved 

 from the shallow, quiet water along the edges into the swift water near 

 the center of the stream or into the deeper holes. 



On the 12th of June the average length of the young steelheads was 

 taken from thirty-three fish measured, and was found to be 2.6 inches. 

 The age of these fish we can estimate very accurately to be fifty days, 

 counting from the time their yolk sacs were absorbed. At the time of 



