Figure 10. Relative Abundance of Yellowfin Tuna in 

 the Western Equatorial Pacific. To obtain information on the dis- 

 tribution of yellowfin tuna throughout the Pacific Ocean, we have 

 obtained data from the nine Japanese mother ship expeditions to the 

 western equatorial Pacific in 1950 and 1951. These fishing trials 

 were restricted by SCAP to the area from 130° to 180° E. longi- 

 tude and from the Equator to 24 N, latitude. Our observers went 

 along on five of the expeditions to collect biological data and pro- 

 duction records. 



This figure gives the catch rates as averages for yel- 

 lowfin tuna from all expeditions. The contour lines in the figure 

 separate zones of like catch rates. The Japanese fishing in the 

 western Pacific agrees withPOFI'sin the central Pacific by show- 

 ing yellowfin to be most abundant near the Equator and tapering 

 down to the north; however, the abundance is very much lower . 

 The best western areas produced only 2.5 yellowfin per hundred 

 hooks whereas the best areas in the central Pacific produced over 

 9 and there was a very large area that averaged 6 fish per hundred 

 hooks. 



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