contained Euphausiacea in quantities meriting up to the index 3-4. ]_l 



Month // /// ly V VI W m IX X XI Xh 



Figure 1. Stomach fullness of Atlantic -Scandinavian herrings in different months. 

 1. Stomach empty; 2. Small food content; 3. Moderate food content; 

 4. Stomach full and distended. 



In March, Thysanoessa inermis , Themisto abyssorum , Themisto compressa f . bispinosa , 

 occasional sjDecimens of Pareuchaeta norvegica , etc. are found in the plankton in addition to Megan- 

 yctlphanes norvegica . At this season, the herring, after spawning, leave the spawning grounds 

 and begin to feed intensively in the northward -moving currents of warm water. 



In March 1951 (sample 3, Figure 3), the principal food components of the herring were 

 Meganyctiphanes norvegica and Thysanoessa inermis , which constituted 55% of its diet. In addition 

 to the above-named species of Euphausiacea, the food of the herring contained Themisto compressa 

 f . compressa, Th. compressa f. bispinosa , C. finmarchicus and up to 20% young wolf fish. In 1954 

 (sample 4, Figure 3), the food of the herring consisted entirely of Euphausiacea. 



In April, the accumulation of plankton increases and the composition of the food of the herr- 

 ing becomes more varied in kind. A number of sf)ecies which are very nimierous in some years 

 make their appearance. Thus, in April 1952 (sample 5, Figure 3), Calanus finmarchicus amoiinted 



1/ Index 3 = stomach full. Index 4 = stomach distended. 



148 



