is more uniform than between those near the focus. The lateral field was 

 chosen in preference to the anterior field because the coarser spacing of 

 the former facilitates counting and because there is closer agreement be- 

 tween several scales taken from the same fish. The vddth of the band com- 

 prising ten circuli was measured from three scales from each fish. Fre- 

 quency distributions of the averages of these three measurements are pre- 

 sented in Tables 26, 27 and 28. In Table 26, only those 0-group weakfish 

 taken in October or November are included in order t o exclude individuals 

 which had not cortpleted their growth for the season. 



An examination of these frequency distributions indicates differences 

 between year classes at the same location. As an example, an analysis of 

 variance of the Montauk,N.Y. samples for 1930, 1931, 1932, and 193U gives 

 the following results: 



Degrees of Sum of Mean 



Source Freedom Squares Square 



5.3 



667, U3U 



663, 38U 



85 



3,965 



?<. 0.01 



28.33 

 5.3h 



Since there are significant differences in meaj:urements between differ- 

 ent year classes at the same geographical location, it is necessarj'' to 

 seoarate year classes before making any comparison between geographical 

 areas. From table 26, measurements can be obtained for the 193U C-group 

 ■weakfish for North Carolina, Virginia (Exmore and Chesapeake Bay) , and 

 northern localities (wildwood, N. J., Northern New Jersey, and Montauk, 

 N. Y.) . Analysis of variance gives: 



The (differences indicate separate populations — a southern group and 

 a northern group. The difference between Nort> Carolina and Virginia, 

 however, is not significant (F = 0.29, d.f. = 1 and 233, P> 0.05) . 



It has been sho^m that differences exist between year classes in the 

 same locality. To learn whether I-group fis'i spend their first summer in 



67 



