WIESEL. HANZEL. and NEWELL: PYGMY WHITEFISH IN MONTANA 



Table 5. — Length frequency of age groups of pygmy 



whitefish from Flathead Lake, 1967-7 L 



[ F, females; M, males. ] 



1 I 



AA F 



84 -1 — — — — — — — 1 



89 1— — — — — — — 1- 



91 __ __ __ __ __ 



94 1— -— -— — - 1- 



99 1— — - -- -- 1- 



102 1— — - -- -- 1- 



104 2- 1- -- — - 3 — 



107 41 — — — — — — 41 



109 83 11 — — — — 94 



112 82 -- -- -- 82 



114 31 2 — 3 — — — — 31 5 



117 213 1— — — — — 22 3 



119 18 2 5 — — — — — 23 2 



122 10 — 2 1 — — — — 12 1 



124 6 1 5 1 — — — — 11 2 



127 5 — 7 1 — — — — 12 1 



130 -- 5- -- -- 5- 



132 2 — 12 8 - 1 — — 14 9 



135 1— 43 — — — — 53 



137 — 3 76 — — — — 79 



140 — — 15 1— — — 25 



142 — — 25—1 — — 26 



145 — — 37 — — — — 37 



147 — — 34 — — — — 34 



150 — — 14—1 — — 15 



152 — — — 4 — 2 — — — 6 



155 — — — 3 — 2 — — — 5 



157 -- — 1 -1 — — — 2 



160 — — — 1 — 4 — — — 5 



163 -- -- -- -2 -2 



170 -- -- -- — 1 -1 



AAean 



length 116 116 129 140 132 153 — 165 121 138 



Total 



number 120 18 60 58 1 12 — 3 181 91 



Superior. Growth was nearly the same in Bull 

 Lake. The initial growth of the Flathead Lake 

 population was exceeded in Wood Lake, Alaska, 

 and after the third year in MacLure Lake, 

 British Columbia, where the fastest growth 

 rate has been reported for the species (Figure 2). 

 Both Bull Lake and Flathead Lake collections 

 indicate that few males live beyond their third 

 growing year whereas some females reach the 

 fifth growing year. Data from Wood River and 

 the Naknek River systems in Alaska and from 

 Lake Superior also show that females are longer 

 lived. Females in Wood River can attain age VI 

 and those in Lake Superior attain age VIL 



260 



220 



180- 



3 4 



GROWING YEAR 



180- 

 160- 



I 140 



t- 



5 120-1 



_l 



< 100- 



I- 

 o 



- 80 



60- 



LENGTh= 



0.9132 SCALE RADIUS + 61.6306 



I I I 1 1 1 



20 40 60 80 100 120 140 



ANTERIOR SCALE RADIUS (mm « 67) 



Figure 1. — Body length-scale radius relation of pygmy 

 whitefish from Flathead Lake. Solid line is calculated 

 equation; circles represent mean body lengths for given 

 scale radii; dashed line connects estimated intercept at 

 25 mm length at scale formation. 



Figure 2. — Calculated growth of female pygmy whitefish 

 from Flathead Lake compared with data from Bull Lake 

 and Lake McDonald, Mont., and Lake Superior (Esch- 

 meyer and Bailey. 1955); Wood Lake, Alaska (Rogers, 

 1964); Brooks Lake, Alaska (Heard and Hartman, 1966); 

 and McLure Lake, British Columbia (McCart, 1963). 



FOOD HABITS 



The importance of major food items of the 

 pygmy whitefish of Flathead Lake shifts from 

 month to month, undoubtedly according to 

 availability. Chironomid larvae and pupae were 

 the most important items consumed both by 



591 



