1 82 The Lije Story of the Fish 



to the side and forward of the pit, the material displaced by 

 her being carried into it by the current. Within a minute or 

 two the eggs are well covered, and she moves upstream a 

 short distance and begins a new nest. As she works on this, 

 sand and gravel are carried downstream over the first exca- 

 vation until it is turned into a mound projecting above the 

 stream bed, and the eggs are protected by a layer of gravel 

 four to eight inches deep. Steelhead characteristically start at 

 the bottom of a suitable spawning area and work upstream, 

 placing their egg-pits almost in a straight line with the 

 current in a manner highly efficacious for the utilization of 

 hydraulic forces, but other species do not always do so, the 

 later nests sometimes being to the side of or even below the 

 earlier ones. In all cases, work is done at the first site to 

 cover the eggs 5 the protecting over-layer of gravel is not 

 merely the fortuitous result of a later upstream spawning, 

 but is definitely the completion of the spawning act at that 

 point. 



This process of nest-building, courtship, and spawning is 

 repeated several times and may continue for anywhere from 

 a day to a week before the female is rid of all her eggs. 

 Mother and father then forget about family life and go their 

 separate ways. 



The whole spawning pattern is essentially similar in the 

 rainbow, the cutthroat, the brown trout, and the various 

 species of Pacific salmon, but in the eastern brook there is 

 one variation which may have considerable significance. The 

 female covers her egg-pit not by going upstream and flapping 

 up gravel which the current carries over it, but by using her 

 anal fin to sweep gravel over the pit from its edges. This is 

 a much less efficient method than that described above where 

 the current did a large share of the work; but it can be 

 seen that it would produce a protective mound even where a 

 current was lacking. Now, you will remember that the east- 



