whose average fork length was 14 inches (14.8 

 inches, total length) and whose average weight 

 was 1 pound (table 10) . However, nearly half 

 (46 percent) of the males were mature as age- 

 group m whereas only 10 percent of the III- 

 group females were mature. Apparently males 

 tend to become mature at an earlier age than 

 females. No well represented age group of 

 either sex was composed entirely of mature fish. 



Since nearly all of the Il-group males 

 were immature in August, it may be assumed 

 that very few males of this group spawn when ex- 

 actly 3 years old (in spring) . Since nearly half 

 the ni-group males were mature in August, it 

 may be assumed further that these fish were at- 

 taining sexual maturity for the first time at 4 

 years of age. Thus, if half the male walleyes 

 are to be permitted to spawn once, they must be 

 protected until their fifth summer; and if more 

 than half are to spawn once, protection must be 

 provided until the sixth summer . By a similar 

 reasoning it may be determined that the majority 

 of the females reach sexual maturity for the first 

 time when exactly 5 years of age, and protection 

 must be provided until they enter their sixth 

 summer. These findings disagree with the state- 

 ment of Surber (Minnesota Conservationist, 

 February, 1934, p. 18) that walleyes mature in 

 3 years. 



Table 10 indicates that males in their 

 sixth summer (August) averaged 14 inches, fork 

 length (15 inches, total length; 1 .05 pounds) and 

 the females 15 inches (15.9 inches, total length; 

 1.23 pounds). The average for both sexes com- 

 bined was 14.8 inches, fork length (15.7 inches, 

 total length; 1.2 pounds). 



Data on percentage of maturity at differ - 

 ent lengths (table 16) indicate that male walleyes 

 mature at a smaller size as well as at a lower 

 age in comparison with females. Although little 

 difference exists between sexes in the length at 

 which the first mature individuals occurred, a 

 majority of the males were mature or maturing 

 at all lengths beyond 280 millimeters, standard 

 length, (12.5 inches, fork length) as compared 

 with a length of 300 millimeters (13.4 inches, 

 fork length) for females. Table 16 indicates 

 that at 14 inches, fork length, 19 percent of the 

 males and 36 percent of the females may still be 



immature. At 15 inches, fork length, all of the 

 males and 89 percent of the females were 

 mature . 



To obtain adequate data on age and 

 length of walleyes at first maturity, it was neces- 

 sary to include both selected and unassorted 

 samples in the tabulation. The inclusion of the 

 data of selected fish causes the percentages of 

 immature fish in the entire sample to be higher 

 than would be expected in a strictly random 

 sample of the commercial catch . In the unas - 

 sorted sample of the commercial catch from 

 3 -1/2 -inch mesh nets, of a total of 47 males, 

 78 percent were mature; of a total of 80 females, 

 72 percent were mature . 



Numbers of males and females in each 

 age group and sex ratios were as follows: (The 

 sex was not determined for one 0-group fish.) 



Number Number of Females per 

 Age group of males females 100 males 



Among the younger age groups (I-IV) the repre- 

 sentation of the sexes tended to be nearly equal. 

 Females were strongly predominant, however, 

 in age -groups V and VI. Females outnumbered 

 males in the complete sample in the ratio, 

 143:100 (For sex ratios during the spawning 

 season see table 22.) 



Spawning habits and season 



Walleyes of the Red Lakes spawn during 

 the last half of April and early May and the eggs 

 hatch in May and June . TTie actual dates on 

 which spawning begins and ends vary somewhat 

 in different years in accordance with weather con- 

 ditions. The following List of dates when ripe 

 eggs were collected for artificial propagation 

 shows actual spawning dates in some years: 



1932. April 19 to May 4; peak. April 22 to 28 . 



38 



