HERRING IN PRINCE WILLIAM SOUND, ALASKA 
289 
2. The means of the vertebral counts of each year class of herring in Prince 
William Sound showed a very high negative correlation, —0.85, with the tempera- 
tures during the period in which the eggs and larvae of each year class were spawned 
and developed, showing that the differences in the means of the vertebral counts 
within Prince William Sound are chiefly, if not wholly, due to environmental con- 
ditions and not to genetic differences. 
3. Comparisons of the means of the vertebral count distributions of fish of the 
same year class from neighboring localities suggest that McClure Bay has a stock of 
herring independent of those caught elsewhere in Prince William Sound but can 
not be definitely said to differ without further data. 
4. The availability of the herring schools to the fishermen varies widely during 
different portions of the fishing season, as shown by the catch per boat per 10-day 
period, being highest during July, reaching a low point about September 20, rising 
to a second peak during the period from September 23 to October 2, and then fluc- 
tuating at a low level until the end of the season. 
5. The herring normally enter the commercial catch in true proportion to their 
relative abundance during their fourth summer, although exceptionally rapid growth 
may cause the fish to enter the catch in large numbers during their third summer. 
6. The great fluctuations in abundance that have occurred in Prince William 
Sound have been due largely to the growth and passage through the commercial 
catch of fish of dominant year classes. 
7. In order to avoid violent fluctuations in the yield of the fishery a reserve of 
older age classes must be maintained. 
8. The only regulations that have had a limiting effect on the fishery are those 
defining the fishing season. 
9. In the period from 1925 to 1930, inclusive, the closed periods for fishing have 
probably decreased the total catch from about 9 to 28 per cent in the various years. 
10. The present fishery is losing much profit by taking large quantities of young 
herring for reduction, that should be permitted to reach an age of 6 years and over 
before being caught. 
RECOMMENDATIONS 
FUNDAMENTAL CONSIDERATIONS 
In order to prevent a recurrence of a scarcity of herring as in 1926 and 1927, 
or of the lack of fish of pickling size that characterized 1928, 1929, and to a large 
extent 1930, it will be necessary to protect the 1926 year class (now composing the 
bulk of the catch) until sufficient numbers of herring of another or other year classes 
also reach pickling size. As mentioned elsewhere the 1927 year class was poor. 
From the great scarcity of 3-year-olds in the 1930 age distributions it is extremely 
probable that the 1928 year class was a practical failure. In applying protection 
to this fishery one must not be mislead by the present abundance (due wholly to 
the 1926 year class), as year classes as abundant as that of 1926 are the exception, 
so that adequate protection must be given during periods of abundance if the fishery 
is to avoid periods of great scarcity. 
The catch may be limited by restrictions on gear, fishing season, localities 
fished, or the size of fish taken. However, each type of regulation has its own 
peculiar advantages and disadvantages. Regulating the size of fish to be taken, for 
instance, is not very practicable in a purse seine fishery, as the gear catches all sizes 
