GRAYLING SPAWNING REPORT 



We do not plan r.a allow these fish more than two generations, and 

 preferably only one, of lake residence prior to our returning for 

 eggs to supplement the Big Hole population. The exception to 

 that would be if the Big Hole grayling population went extinct 

 due to a catastrophic event. 



The issue of competition and predation will have to be 

 addressed by conducting the research to determine if these two 

 factors contribute to significant mortality within the Big Hole 

 River grayling population. It would be premature at the present 

 time to suggest acting on this possibility without further 

 evidence. 



The possibility of re-establishing riverine populations of 

 grayling into waters in Montana which do not presently support 

 them should be addressed. At the present time it appears that 

 re-establishing grayling populations will be difficult, at best. 

 The experience that U.S. Fish and Wildlife Service biologiats 

 had in Yellowstone ^^atiDnal Park trying to re-establish a 

 grayling population into Canyon Creek, a tributary to the 

 Firehole River, suggests that rivt^rine populations require 

 relatively large drainage? systems that sltb accessible. It the 

 Canyon Creek experiment, a falls on lower Canyon Creek was 

 enhanced to provide a total barrier to upstream migration so thax 

 exotic species of fish could not ascend Canyon Creek and coa^;pet3 

 or prey on the grayling population re-introduced into Canyon 

 Creek. An attempt was made to renove all fish within Canyon 

 Creek prior to the introduction of grayling v-jhich were obtained 

 from the Big Hole River. However, it appears that these 

 introduced grayling moved out of Canyon Creek, probably seeking 

 winter habitat, and could not return. This suggests that it will 

 not be possible to re-establish populations of riverine grayling 

 into small isolated tributaries, but will require medium to large 

 river drainages which can provide spawning, summer feeding, and 

 overwintering habitats. The effort to accomplish this type of 

 re-introduction would be immense and may mean that existing fish 

 species could not be removed prior to grayling re— introduction . 

 The potential for re-establishing riverine grayling in Montana 

 where they do not presently exist will require more research and 

 a strong commitment to that type of effort. 



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