w 



Lower Beaver Creek is distant from any population center and access 

 is extremely poor in wet weather, explaininq the low level of exploitation. 



Age and Growth . The lenqth-weiqht relationship of fish can be 

 represented by the formula: w = al° (log w = loq a + b (log 1)). where 

 w = weight, 1 = length, b = regression coefficient and log a = y intercept. 



The functional regression value b = 3 describes isometric growth, 

 such as would characterize a fish having an unchanging body form and 

 unchanging specific gravity, b values greater or less than 3 characterize 

 allometric growth: if b= 3, the fish becomes "heavier for its length" as 

 it grows larger. There are sometimes marked differences between different 

 populations of the same species or between the same population in different 

 years presumably associated with their nutritional condition. 



A total of 68 walleye were captured during 1978 in Beaver Creek and 

 figure 19 illustrates the length-weight relationship of these fish. The 

 growth rate of walleye in Beaver Creek is generally slower than walleye 

 in the Tongue River Reservoir (Riggs 1978), however, Beaver Creek walleye 

 have a faster growth rate than walleye in the Yellowstone River and 

 Columbia River drainage in Montana (Peters 1964). 



The length-weight relationship (Figure 20) was derived from the 

 measurement of 48 sauger captured during 1978. The growth rate of sauger 

 in Beaver Creek is similar to sauger in the Tongue River Reservoir (Riggs 

 1978) and generally higher than sauger in the Yellowstone River, Fort Peck 

 Reservoir, Milk River, Missouri River (Peters 1964) and Lake Winnebago 

 (Priegel 1969). 



Channel catfish . Channel catfish are also present in the lower reaches 

 of Beaver Creek near its confluence with the Little Missouri River. A total 

 of 14 individuals were captured in section 1 during May of 1978 when 

 water temperatures ranged from 12-20OC (54-680F). This species was 

 observed as far upstream as section 25 and fishermen reported an occasional 

 catfish caught at Wibaux. 



Spawning of channel catfish generally occurs at temperatures between 

 70 and 850F (21-290c) (Clemens and Snead 1957). Those temperatures 

 were common during late June in 1978, however, runoff from rainstorms 

 precluded any sampling during this period (Figure 21). Young of the year 

 channel catfish were collected in section 1 during August and September 

 and section 25 in September indicating that channel catfish utilize lower 

 Beaver Creek for spawning and rearing. 



Channel catfish probably move up Beaver Creek from the Little Missouri 

 River. After the spawning season is over and the water levels in Beaver 

 Creek reach summer lows, they probably return to the Little Missouri River. 

 McCammon (1956) found downstream movement of catfish in the lower Colorado 

 River in the fall. Other studies have concluded that channel catfish 

 move long distances upstream and downstream from the point of capture 

 (Harrison 1953, Hubley 1963, Muncy 1958 and Messman 1973). Van Eeckhout 

 (1974) found that flows delineate when and how much catfish move 



■56- 



f^ 



