In such years, the temperature in the waters of the Norwegian current rises, the early dev- 

 eloping Calanus in July leave the surface layers, where there is an abundance of jellyfish, which 

 are unsuitable as herring food. 



Figure 13. Distribution of the plankton biomass in the 0-50 meter layer in the Norwegian 

 and Greenland Seas on June 1-26, 1954. 1. pre -spawning accumulations of 

 Calanus ; 2. nauplii and young of Calanus; 3. red Calanus at the surface; 4. 

 red Calanus descended into the deep; 5. Phaeocystls ; 6. diatoms; 7. Calanus 

 hyperboreus ; 8. jellyfish. (See Figure 12). 



Due to the acceleration of the cold East Greenland current, linked with the Norwegian cur- 

 rent, the zone of mixed waters becomes narrower and the herring of the older age groups do not 

 enter the waters with a low temperature that are west of Jan Mayen. The main bulk of them leave 

 for the far north in search of food; the length or duration of the migration routes increase. But 

 these migrations help little with regard to the concentration or storing of fat in the herring. 



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