From this we see that altogether more than half of all the spring herring taken du- 
ring these seven years belonged to the 1904 year class. The figures and the graph show 
the increase in the number of individuals in the years 1907—1910, at the time when 
the immigration from the fat herring shoals took place. After that, the yield varies 
considerably. We may certainly say that the 
fishery since 1910 has been rich and extensive, 
and that the year class has in all years exhibited 
such a degree of wealth as even to warrant the 
anticipation, in one year, of a good yield in the 
next. There is however, no full and complete 
agreement with what one might expect to find, 
from the percentages for the year class in the 
samples examined. According to these, the 
greatest number of individuals should have 
been taken in 1910, when the percentage was 
77.0, and later somewhat less. This discrepancy 
can evidently only be explained by the supposi- 
tion that the catches in these years have not 
made up the same percentage (percentage of fish 
caught) of the whole stock. In order to under- 
stand the fluctuations of the fishery, it is there- 
fore evidently highly necessary to be acquainted 
with the variations of the year classes; it must, 
however, continually be borne in mind that 
other conditions may also play an important 
part 
Many factors may of course be found to 
account for the fact that the proportion of the 
stock taken im the course of the fishery varies 
from year to year. We have first of all the 
factors upon which the whole industry depends, 
viz. weather conditions and ruling prices. In 
addition to this, the movements of the fish will 
also be of great importance. In some years, 
the fish move at so great a depth as to render 
it difficult for the fishermen to reach them. In 
others, it must be supposed that the stock, for 
Mil... 
endividi 
680 
600 
50 
400 
a 1907 08 09 10 77 72 1913 
Fig. 29. Yield of spring herring tor the years 
1907—1913, in millions of fish. 
Theblack columns represent 1904 year class. 
instance, of spring herring, seek other waters-than those where the fishermen have 
assembled to await their arrival. 
As already mentioned, spawning herrmg were taken in 1910 on the Faroe banks; 
these fish undoubtedly belonged to the Norwegian spring stock. 
In 1903, K. Dax1*) carried out some fishing experiments for cod (“skrei”’) on the 
so-called Haltenbank (between 641/,° and 65° N. Lat.). He encountered here an exten- 
*) Undersokelser over skreibanker paa strekningen Trenen—Kristianssund. Aarsberetn. vedk. 
Norges fiskerier. Bergen 1904, 
6* 
