Ul 



o 



UJ 



100 

 90 

 80 

 70 

 60 

 50 

 40 

 30 

 20 

 10 

 



— I 1 1 \ r 



B SPENT 



■ MATURING a RIPE 19 



NUMBERS INDICATE 

 THE NUMBER OF 

 OBSERVATIONS 



Figure 14, Tuna Spawning Near the Equator. In ad- 

 dition to knowledge of the abundance of yellowfin tuna in the central 

 Pacific it is essential to understand the distribution of the different 

 populations found throughout the Pacific, One method of accom- 

 plishing this is to study the spawning habits of tuna found near the 

 Equator, We have examined the roes in a large number of the 

 yellowfin captured during our fishing trips. A high percentage of 

 these fish caught during all months sampled were either nearly 

 ready to spawn or were spent. Somewhat more spawning activity 

 is suggested during the summer and fall months than at any other 

 time of the year, but some spawning yellowfin were obviously 

 present throughout the year. 



Although the condition of the roe proves that the yel- 

 lowfin would spawn in the near future or had done so in the recent 

 past, very few actually running ripe fish are caught. This leaves 

 some doubt as to the exact spawning place. Much of this doubt is 

 removed by our finding the very young tuna larvae in our plankton 

 hauls from the equatorial area. 



15 



