GRAYLING OF GREBE LAKE 



319 



Figure 8. — Hatchery Creek trap (with wire-mesh superstructure to keep out bears) in August 1952 after iron rack was 

 removed (at arrows) and fish were allowed access, looking westerly downstream with Grebe Lake in distance. 



surface at this time were much like those of the 

 streams. 



Within the foregoing extremes there were 

 behavioral differences within and between the 

 two kinds of fishes in the lake (fig. 11). The trout 

 did not have the definite peak of spawning migra- 

 tion (as reflected by movements into traps) that 

 the grayling attained. In most streams spawning 

 travel started 1 to 3 weeks earlier for the trout 

 than for the grayling (tables 11 and 12), and 

 continued at a more or less steady rate throughout 

 the spring over the entire temperature span given 

 above. The range of daily averages was from 40° 

 F. to 50° F. when the grayling runs were heaviest. 

 Temperatures near the surface of Grebe Lake 

 were above 45° F. each year when grayling 

 migrations were maximal (fig. 11). 



485001 0-59-3 



Spawning Populations of Grayling and Hybrid Trout 



There were 10 to 20 times more grayling than 

 trout ascending the spawning streams in 1953 and 

 1954 (table 13). The actual grayling-trout ratios 

 were 10.5 to 1 (1953) and 19.5 to 1 (1954). The 

 difference in ratios in the 2 years might have 

 resulted from comparing an incomplete count 

 (possibly selective) in 1953, with a relatively 

 complete one in 1954. In the later year, blockades 

 on Northwest Creek, Creek 2, and South Creek 

 seemed to have forced many spawners to accept 

 either the outlet or Hatchery Creek as their 

 spawning site. This may have resulted in larger 

 counts on these two streams than would otherwise 

 have occurred. 



Records of spawntakers enumerating weir cap- 

 tures in years previous to 1953 showed that few 



