Weight Frequency 



Table 6 gives weights of sturgeon captured in 1975 and 1976. Of the 

 sturgeon examined in 1975, 23.7 percent exceeded 2.7 kg (6 lb), 7.6 percent 

 exceeded 3.6 kg (8 lb), and I.d percent exeeded 4.5 kg (10 lb). In the 

 1976 sample, 21.6 percent exceeded 2.7 kg (6 lb), 6.7 percent exceeded 3.5 kg 

 (8 lb), and 1.8 percent exceeded 4.5 kg (10 lb). The weights of the 1974 run 

 were similarly distributed (Peterman and Haddix 1975). A sample of sturgeon 

 migrating into the Powder River averaged 2.42 kg (5.33 lb), showing 

 close agreement with the Tongue River samples (Rehwinkel et al 1976). 

 Figures 8 and 9 are weight-frequency histograms of sampling in 1975 and 

 1976, respectively. 



TABLE 6. Weights of shovelnose sturgeon captured in the Tongue River in 1975 



and 1976 



Shovelnose sturgeon captured in the Tongue River during the spring 

 migration were considerably larger than those reported elsewhere. In the 

 lower Missouri River, the average weight was 0.45 kg (1.0 lb), with 

 1.8 kg (4.0 lb) fish considered rare (Schmulback 1974); Helms (1974) 

 found that the average weight of Mississippi River shovelnose was about 

 1.1 kg (2.5 lb). Brown (1971) reported that 4.5 kg (10 lb) was 

 considered maximum shovelnose weight and that 3.2 kg (7.0 lb) was the 

 Montana record. While the Tongue River sample is of a spawning population, 

 the presence of considerably larger fish appears significant. 



Length-Weight Relationship 



The length-weight relationship was calculated for 874 shovelnose 

 sturgeon, utilizing the formula (Ricker 1975): 



w = Cix 



where: w = weight in grams 



1 = length in millimeters 



C, X = constants 



29 



