commercial catch as determined from a series 

 of unassorted samples. 



With the exception of the -group the 

 frequency distributions of the successive age 

 groups overlap; this overlap increased with in- 

 crease in size and age . Every length interval 

 beyond 240-249 millimeters, standard length, 

 was represented by fish of two or three age 

 groups. 



All walleyes of age -groups 0, I, and II, 

 and all but one of the III group were below 14 

 inches fork length . Forty-six percent of the IV- 

 group fish, and 21 percent of the V -group were 

 shorter than 14 inches. All individuals of the 

 age -group VI were well above 14 inches, in the 

 winassorted samples (782 fish) from the commer- 

 cial catch, 38 percent were below and 62 percent 

 above 14 inches. 



The range of length over which the gill 

 nets took walleyes in abundance was delimited 

 sharply. Seventy -six percent of the total catch 

 fell within the length range, 13.4-15.6 inches, 

 fork length (14.2-16.6 inches, total length. 

 0.9-1.4 pounds). Nearly all of these fish be- 

 longed to age -groups FV and V . The irregular 

 and discontinuous distribution of the smaller fish 

 suggests that many of them were accidental" 

 captures, that is, were not gilled in the custom- 

 ary manner but were entangled in the webbing of 

 the nets by their mouth parts, teeth, or fins . 

 No individual exceeded 17.5 inches in total lengJi. 

 An attempt to obtain larger specimens failed. 

 One informant asserted that in the period 1927- 

 1932, the walleye averaged much larger; fish 

 of 4 or 5 pounds were common in the earlier 

 period, when a 4 -inch mesh gill net could take 

 them in the deeper water . 



Rate of growth 



Lengths, weigjits, and coefficients of 

 condition of each age group of the Lower Rad 

 Lake walleye are shown in table 10 for each sex, 

 and calculated lengths according to age group or 

 year of life are presented in table 11 and fig. 2 . 

 Inspection of average lengths at time of capture 

 shows no differences or only slight differences 

 between males and females of age -groups I, II, 

 and III, but females of age -groups IV and V 



averaged distinctly longer than the males. (The 

 scanty data of age-group VI do not permit a com- 

 parison of the sexes.) The average weights show 

 a similar sex difference in age -groups IV and V, 

 where females averaged slightly heavier than 

 the males 



The calculated standard lengths at the end of 

 the first year of life (table 11) were higher in age- 

 group I than in any of the older age groups . The 

 small fish were taken in large -mesh gill nets and 

 probably were the larger and more rapidly growing 

 members of the age group . The same explanation 

 applies to the larger of the two 0-group fish that 

 were 89 and 116 millimeters, standard length, 

 at the time of capture . The calculated lengths 

 of age-groups U-VI doubtless were affected less 

 by gear selection and may be taken as descriptive 

 of the growth history of the population. The cal- 

 culated lengths shown at the bottom of table 11 

 are based on data of age-groups II-VI. Age-group 

 I was excluded from these compilations since it 

 was probably unrepresentative. The grand 

 average calculated lengths represent the succes- 

 sive summations of the grand average annual 

 increments of growth in length. This procedure 

 provides a smoother growth curve and one more 

 in conformity with the actual data on the growth 

 in different years of life . 



In all the well represented age groups 

 except the II group, the calculated lengths of 

 the females tended to be greater than those of 

 males, especially during the later years of life . 

 This superiority in the growth of the females 

 may be seen also in the grand average calculated 

 lengths. (See also fig. 2.) The advantage of the 

 females was insignificant (only 1 millimeter) at 

 the end of the first year of life but increased 

 continuously with increase in age to a maximum 

 advantage of 19 millimeters at the end of the 

 sixth year . The most rapid growth of both sexes 

 occurred in the first year of Life. Growth in- 

 crements decreased in each of the later years 

 but the decline was most rapid in the third and 

 fourth years. 



Comparison of the growth in Lower Red 

 Lake and in other waters 



Calaulated lengths and annual increments 

 of length for the various years of life of walleyes 



27 



