1990 Grayling Spawning Report 



Table 4. Average depth (ft.), velocities at 0.6 and 0.1 depth 

 ( f ps ) , and surface substrate composition (%) at capture 

 locations of ripe and mature grayling (USED) and at 

 adjacent (AVAIL) areas. Sample sizes in parentheses. 

 Data from 11 capture site locations sampled during the 

 1989 spawning run. 



Velocity ( f ps ) 



Depth 0.6 0.1 

 (ft^ depth depth 



Surface substrate (%) 



Small Large 

 Silt Sand gravel gravel Cobble 



AVAIL 1.8 1.6 0.9 14 23 

 (84) (76) (72) (80) 



32 



24 



USED 2.2 1.9 1.1 11 

 (28) (28) (27) (28) 



20 



32 



31 



water (Figure 6 and 7) for spawning and also select areas over 

 cleaner (less sand and silt) substrate which contains higher 

 percentages of large gravel. The stream substrate results tend to 

 support the supposition (based on limited hollow core data) of 

 Shepard and Oswald (1989) that grayling may need relatively clean 

 substrate with a small percentage of fine sediment on the surface 

 for spawning. These results must be viewed with caution because 

 there is no way to determine exact spawning locations using 

 electrof ishing. 



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