104 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



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MILES FROM LAND 

 Figure 8. — Variation in availability of the major food categories with distance from land, for longline-caught yellowfin, 

 as indicated by average volume per stomach. N = number of stomachs. 



Relation of volume of stomach contents to oceano- 

 graphic conditions 



On cruise 11 of the Hugh M. Smith, longline 

 fishing was conducted at a series of stations along 

 150° W. longitude, ranging from about 15° N. to 

 5° S. latitude. A single oblique plankton haul to 

 a depth of 200 meters was made daily at each 

 station. The volume of zooplankton at each 



station, expressed in cubic centimeters for each 

 cubic meter of water strained, and the catch of 

 yellowfin per 100 hooks fished at each station are 

 given in figure 10. For purposes of comparison 

 the cruise area may be divided into (1) An area 

 of poor tuna catch, north of 6° N. latitude; 

 (2) an area of good tuna catch at 6° to 4° N. 

 latitude; (3) another area of good catch at 3° to 



