AVERAGE 

 PLANKTON VOLUMES 



1959 COMPARED TO 1958 ANO 1951-1956 AV. 



1931 tdru 1936 I 

 1938 

 1959 



_3» 



Figure 2.--Average plankton volumes in 1959, by month, compared with average volumes 1951-1956, 

 and average volumes in 1958, for the two areas shown on map. 



