N 
decreases, that of the fat herring (Stages | and Il) increasing. The change from May 
to July must therefore be due to an immigration of fat herring. 
In order to discover whether this is to be regarded as a fact peculiar to the year 
1911 or as a phenomenon of common occurrence, we will now compare the maturity 
WD A) WE le 
ZAG EE PE ee 
Fig. 46. Composition in point of age of three herring samples from the Shetlands. 
1. July 1910. 2. July 1911. 3. July 1912. 
and composition in point of age of the Shetland herring for the months of June and July 
in 1911 and 1912. Fig. 44 shows the maturity in June and July 1912. If we compare 
this with Fig. 43, we find that there was in both years a large amount of fat herrmg pre- 
sent, most in 1912. Each of the two years exhibits great similarity between the two 
