PACIFIC HERRING 
271 
from each main group do not overlap the curves for the other main groups, except in 
the cases of Dogfish Bay and Halibut Cove, 1927 (which, as mentioned before, may be 
due to condition), is sufficient proof of the real significance of at least the main groups. 
3. The head lengths separate the populations of Prince William Sound from those 
of the Kodiak-Afognak district and of Kachemak Bay— a distinction of stocks not 
shown by the vertebral counts. 
OTHER CHARACTERS 
Besides the structural characters there are other differences between the stocks 
of herring that while not strictly “racial” differences yet indicate the degree of inde- 
BODr LENGTH IN MILLIMETERS 
Figure 22.— Percentage head length is of body length. Showing: A, Southeastern Alaska; B, Prince William Sound, 
(1) Naked Island 1927, (2) McClure Bay 1927, (3) Naked Island 1925, (4) Elrington Passage 1925, (5) Macleod Harbor 
1927, (6) Eshamy Bay 1926, (7) Elrington Passage 1927, (8) Elrington Passage 1926; and C, Shuyak Strait, lower 
Kachemak Bay, and Halibut Cove 
pendence of the various areas. Since these other characters, such as growth rate, 
size and age composition, condition, and spawning season are treated fully in their 
various sections they will only be alluded to here. The differences in size and age 
composition (and growth rate) between the herring of Prince William Sound and the 
other central Alaska localities, for instance, are large enough to indicate the essential 
independence of Prince William Sound and the areas farther west. And such dif- 
ferences in growth rate as those between Unalaska and central Alaska or Stephens 
Passage are certainly indicative of the independence of the stocks of herring involved. 
