GRAYLING SPAWNING REPORT 



prDgrsssively restrxctxng sport angling harvest from a 10 fish 

 limit to a catch and release limit between 1975 and 1983 (Table 

 1). In addition to reducing limits, MDFWP initiated a graduate 

 study on the population in conjunction with the Montana Coopera- 

 tive Fisheries Research Unit (Montana State University, Bozeman, 

 Montana) which was the first in-depth attempt to document 

 grayling population abundance and distribution (Liknes 1981). 



A literature review of grayling spawning requirements and 

 timing found that grayling are annual spawners (Craig and Poulin 

 1975), likely home (Warner 1955; Craig and Poulin 1975; Tack 

 1980), migrate long distances to reach spawning grounds (Henshall 

 1907; Brown 1938; Nelson 1954; Reed 1964; Bishop 1971; Craig and 

 Poulin 1975; Kratt and Smith 1977), initiate spawning migrations 

 immediately prior to or during ice breakup of main stem rivers 

 when water temperatures are 32 to 39 F (Brown 1938; Nelson 1954; 

 Wojcik 1955; Warner 1955; Reed 1964; Schallock 1966; Williams 

 1968; Tack 1971; Bishop 1971; Tripp and McCart 1974; Craig and 

 Poulin 1975; Krueger 1981; Falk et al . 1982), spawn at .^ixter 

 temperatures between 36 to 50 F (Tryon 1947; Wojcik 1954; Rawson 

 1950; Warner 1957; Kruse 1959; Reed 1964; Williams 1968; Bishiop 

 1971; Netsch 1975; Wells 1976; Falk et al . 1982), spawn over a 2 

 to 24 day period (Kratt and Smith 1977), and spawn in current 

 velocities ranging fron 1.1 to 4.8 ft/s (krueger 1981). 

 Selection of substrate --^or spawning varies widely. Spawning 

 usually occurs over gravel substrates (Henshall 1907; Rawson 

 1950; Nelson 1954; Bishop 1971), but may occur over mud-bottomed 

 pools With vegetation (Scott and Grossman 1973). 



Liknes (1981) surveyed the Big Hole River grayling popula- 

 tion during 1978 and 1979 by elec trof ishing and drift net 

 sampling. He found grayling in three sections of the main stem 

 Big Hole River and the lower reaches of 11 tributary streams and 

 believed that the population was confined to the main stsm Big 

 Hole River and tlie lower portions of its tributaries above the 

 mouth of the North Fork Big Hole River. Shepard (1987 and files, 

 Beaverhead National Forest, Dillon, MT) found three additional 

 streams, Fishtrap, O'Dell and Wyman creeks, and Wise River also 

 contained grayling. The grayling in O'Dell and Wyman creeks and 

 Wise River probably originated from grayling drifting out of 

 mountain lakes within the upper Wyman creek drainage. Shepard ' s 

 findings supported the contention of Liknes that grayling were 

 confined mainly to the upper Big Hole River valley tottom, 

 however, Shepard (1986, 19S7 and files, Beaverhe^.d National 

 Forest, Dillon, MT ) and Oswald (files, MDFWP, Dillon, MT) h-ave 

 documented grayling in most of the Big Hole River from Jackson 

 downstream to its mouth. 



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