GRAYLING SPAWNING REPORT 



Grayling in the Big Hole River ?.ppear to be concentrated 

 between Divide and I'Jisdom and use this portion of the river 

 seasonally by moving up into the Wisdom area during the spring 

 with a significant portion of the population normally re,Tiair>ing 

 in this area through the summer before migrating down river to 

 winter habitats. Shepard (19S7) radio tagged adult grayling 

 during the fail of 1986 and found most radioed grayling moved 

 down river out of the Wisdom area, during October. Some years 

 adult grayling do not remain in the Wisdom area during the 

 sumnier, but move^ down river immediately after spawning. It is 

 unclear what cues this early movement but preliminary observa- 

 tions indicate that it is related to severe reductions in flow. 



Lil.nes i,i9Sl) sampled age O grayling within the Big Hole 

 drainage and concluded that grayling spawned sometime during late 

 April or early May. Shepard (1987) attempted to trap spawning 

 graylirig from April 7 through June 25, 1986, as they moved into 

 several tributaries and a channel of the Big Hole River with 

 little success. In 1987 a committee was organized by the MDFWP 

 that included representatives of MDFWP; Population Genetics 

 Laboratory, University of flontana; Montana Cooperative Fisheries 

 Research Unit, Montana State University; Montana Natural Heritage 

 Program — Nature Conservancy; U.S. Forest Service; U.S. Fish and 

 Wildlife Service; r.!ational Park Service; and American Fisheries 

 Society. This Committee recommended and organized a study to 

 collect more detailed information to describe the locations, 

 distribution, and site characteristics of grayling spawning sites 

 within the Big Hole River drainage, and the timing and population 

 characteristics of the spawning run. This report summarizes data 

 collected during the first year of that effort. 



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