Figure 11. Blomass of plankton (In mg/jjjS) in the 0-50 m. layer in June 1952. 



The boundary of the feeding area of the herring in June 1952 is indicated by the 

 continuous line . 



When the temperature falls there is a slowing-down in the development of plankton as well 

 as in the increase of its biomass . 



Table 4 shows the biomass in the area round Jan Mayen in June 1953 at neig^iboring stations 

 of one of the sections . 



According to data obtained by the PINRO Oceanographlc Laboratory in 1952 and 1953, there 

 was a rise in the cold bottom waters ajar Jan Mayen, which explains the sharp reduction in the 

 biomass of plankton at station 89 . 



The influence of temperature on the development and vertical distribution of plankton are 

 clearly illustrated by graphs I, n. III and IV (Figure 14). 



94 



