higher and sometimes lower than maximum 

 concentrations west of long 92 W. 



A variable area of low forage, centered at 

 about lat 1 S between long 85 and 92 W, is 

 recognizable in Figures 1(A), 1(B), 4(A), 

 4(B), 5(A), 7(A), and 7(B). It may extend 

 farther north, as in Figure 7(B), or south, as in 

 Figure 4(A). Another minimum, oriented more 

 or less zonally, appears in Figures 1(A), 1(B), 

 4(A), and 7(B). It occurs between lat 0" and 

 7= N, long 90 W, and the coast. 



Tables 2 and 3 show the percentage volumet- 

 ric composition of night and day skipjack 

 forage, respectively, in the regions of the above- 

 mentioned maxima, in terms of the five cate- 

 gories of organisms for which data are avail- 

 able. The most striking difference is between 



the forage in the maximum in the northwestern 

 part of the area, which consists predominantly 

 of the pelagic galatheid crustacean Pleuron- 

 cudes planipes, and that in the other maxima, 

 where other crustaceans predominate. The tax- 

 onomic groups of forage animals in the maxi- 

 mum at lat 6 -14 N are more equal in quantity 

 than elsewhere, both by night and day. 



DISCUSSION 



Skipjack fisheries presently exist in many of 

 the areas where high concentrations of forage 

 were observed on the EASTROPAC cruises. 

 These include 1) along the American coast, 

 2) in the Galapagos Islands region, centered at 

 about long 91 W and the equator, and 3) in 



Table 2, Percentage volumetric composition of night skipjack forage in the areas of the principal maxima in the 

 EASTROPAC region. 



Table 3. Percentage volumetric composition of day skipjack forage in the areas of the principal maxima in the 

 EASTROPAC region. 



12 



