IIS^W. 



Figure 6. — Distributions of surface temperature, surface chlorophyll a, and red crabs for cruise TO-64-2 and 



locations of contemporaneous tuna catches. 



occurred almost all along the coast on cruise TO- 

 64-2 ; minima, at stations 1, 8, and 31, were between 

 15° and 16° C, and maxima, at stations 53 and 

 54, were between 26° and 27° C. 



Concentrations of surface chlorophyll a ranged 

 from 6.4 to 0.01 mg./m.^ Their generally much 

 lower values than on cruise TO-64-1 reflect some 

 decay in the upwelling regime. Only station 32 

 had a concentration above 1.0 mg./m.^ The isogram 

 of 0.2 mg./m.^ in figure 6 follows rather closely 

 the edge of the cool water, except in the extreme 



northwestern part of the area covered. It pro- 

 trudes farther offshore between lat. 23° and 24° 

 N. than the corresponding protrusion of the iso- 

 therms. The 0.1 mg./m.' isogram (not shown) 

 follows it closely in most areas. 



The position of the isogram showing 40 ml./ 

 1,000 m.^ of red crabs is close to the 21° C. isotherm 

 and the 0.2 isogram of chlorophyll a, except in the 

 northwestern part of the area (fig. 6). In general, 

 relatively high standing stocks of red crabs and 



160 



U.S. FISH AND WILDLIFE SERVICE 



