BLACKBURN and WILLIAMS: DISTRIBUTION AND ECOLOGY OF SKIPJACK TUNA 



200 m 



Figure 11. -Temperature (°C) section from lat. 15°N to 5°S 

 along long. 119°W, cruise Jordan 60, 5-11 March 1971. 



I25°W 



IS^N. 



10^. 



5»N. 



5'S 



<22 



<22 



• JOnOAN 

 » CROMWELL 



>23 



li5«W 



I25'W 



I20°W 



tsru 



KTH 



S*N 



.9-S 



Hsrw 



I5°N 



IIS'W 



lO'N 



5'N 



5-S 



"' if 



<26 



I20*W 



"T 1 1 1 1 r- 



II5*W 



I5*N 



lO'N 



■S'N 



•0* 



5*S 



Figure 13.— Surface temperature (°C) during Part II operations, 

 cruise Jordan 60, March- April 1971. 



sections (Figures 10, 11). The temperature dis- 

 tributions were generally similar to those ob- 

 served on the same meridian at the same time of 

 year during EASTROPAC Expedition (M. 

 Tsuchiya, pers. commun.). Surface temperatures 

 suitable for skipjack, i.e., between 20° and 29°C, 

 occurred at all latitudes on both cruises. 



The distribution of surface isotherms (assumed 

 synopticity) during Part II (fishing) operations on 

 both cruises is shown in Figures 12 and 13. These 

 figures have been compared, using overlays, with 

 all charts of relative abundance of skipjack 



Figure 12.-Surface temperature (°C) during Part II operations, 

 cruises Jordan bl-Cromwell 51, November-December 1970. 



393 



