IIB-'W. 



115° 114" 113° 112° 111° 



Figure 5. — Track and station positions for eruise TO-&4-2. 



occupied on part 2 of the cruise, temperatures were 

 about the same as on part 1 except on August 21 

 and 22, when tliey were about 2° C. higher. Figure 

 6 includes only those tuna occurrences that were 

 recorded for the period August 5-20. The red crab 

 data are given in table 2. 



Detailed surface temperature charts for the area 

 in July and August show in most yeare a different 

 configuration of isotherms fi-om that found in 

 Jime (Anonymous, 1963). Instead of lying more 

 or less parallel to the coast, the isotherms become 

 wavy ; tongues of relatively cool water extend away 



from the coast, separated from each other by 

 tongues of relatively warm water extending to- 

 ward the coast. Figure 6 shows this situation very 

 well ; cold tongues njn offshore from the two prin- 

 cipal upwelling areas identified on cruise TO-64— 1, 

 and the northern area gives rise to at least two 

 tongvies. This distribution is i)robabl3' caused by 

 the eddies that characteristically a^jpear about 

 July and August (Wyllie, 1966). In figure 6 and 

 later figures, the isotherms selected for charting 

 always included those which showed the tongues, 

 if present, in most detail. Temperatures under 20° 



DISTRIBUTION OF TROPICAL TUNAS OFF WESTERN BAJA CALIFORNIA 



159 



