RACES OF HERRING, SOUTHEASTERN ALASKA 
137 
That the northern slow-growing group of herring found in Icy Strait and the 
vicinity of Juneau all belong to the same race cannot be assumed from growth rates. 
A test of the homogeneity of the vertebral count distributions in this area (see A, 
fig. 2) gives an observed z (see illustration in section on vertebrae) of 0.4069. The 
Figure 6. — Percentage length distribu; ; e- • grouped by 3-millimeter categories and smoothed once by three’s, for herring of the 192fi 
> 'ar class caught in 1930 (in their fifth summer). 
calculated z for a probability of 0.05 is 0.3388, and for a probability of 0.01 it is 
0.4909. Therefore, in this case, the observed z is large enough to be of doubtful 
significance. In this test the mean square between the arrays 0.2268 is less than that 
within the arrays 0.5117 which may indicate a difference in variance. It must be 
realized that no definite conclusions as to the racial homogeneity of this area can be 
reached without further data. 
