z 



O 75 

 O 



o 



^ 50 



T 1 1 1 1 1 1 r 



"1 r 



J L 



J I I I L 



1 1 1 r 



NIGHT HAULS 



DAY HAULS 



I RANGE OF VOLUME 



JUNE JULY AUG. SEPT OCT NOV. DEC JAN FEB. MAR APR. MAY JUNE JULY AUG. SEPT OCT NOV DEC. 



A . ) 



Y 

 1957 



r 

 1958 



Figure 4. — Monthly variations in volumes of zooplankton collected by night and by day at the IGY station 



from June 1957 to December 1958. 



FiGUKE 5. — Monthly vertical distribution of temperature at the IGY station from June 1957 to December 1958. 

 92 U.S. FISH AND WILDLIFE SERVICE 



( 



