GRAYLING SPAWNING REPORT 



LIST OF FIGURES 



Page 



1. Map of the Big Hole River drainage 6 



2. Daily discharge (cfs) and mean, minimum, and maximum 

 water temperatures in the Big Hole River near Wisdom, 

 Montana from April through June 1988. Preliminary data 

 collected by the USGS. The time of grayling spawning 



IS shown in the cross-hatched block above the X-axis. . 7 



3. Catch of grayling 8.0 inches and longer in the Big Hole 

 River and its tributaries by date during 1938. 

 Grayling were segregated into ripe male, ripe female, 

 spent f=male, and other classes 14 



4. Length frequency of Arctic grayling captured during the 

 1988 spawning run by half inch length group. Grayling 

 were segregated into ripe male, ripe female, and other 

 classes. Ripe fish included all fish identified as 

 either mature, ripe, or spent . 16 



5. Growth of grayling in the Big Hole River drainage 

 estimated from mean lengths at age 17 



6. Grayling movement assessed from tag return data for 

 grayling tagged during 1987 and recaptured during the 

 spring of 1988 (A) and tagged during the spring of 1988 

 and recaptured later in 1988 (B). The origin of arrows 

 is the tagging location and the arrow's heads indicate 

 recapture locations 21 



7. Composition of a typical riffle streambed site where 

 grayling were found spawning in the main stem Big Hole 

 River and in a similar site where no grayling spawning 

 was documented in the North Fork Big Hole River. All 

 streambed compositions were determined from ten hollow 

 core (McNeil and Ahnell 1964) samples 23 



Page — vii 



