258 
Fishery Bulletin 115(2) 
0.35 
0.25 
0.15 
0.05 
Number of stomachs analyzed 
Number of stomachs analyzed 
0.65 
0.55 
0,45 
0.35 
0.25 
0.15 
0.05 
1.4 
1.25 
1.05 
0.85 
0.65 
< 
D) 
0.45 
0.25 § 
0.05 
Number of stomachs analyzed 
Number of stomachs analyzed 
4.45 
4.05 
3.65 o 
3.25 S 
2.85 i 
2.45 I 
2.05 o 
1.65 g 
1.25 I 
0,85 g 
0.45 
0.05 
Figure 2 
Randomized cumulative prey curves generated by using the Shannon—Wiener diversity index for yel- 
lowfin tuna {Tliunnus albacares) in (A) zone 1, (B) zone 2, and (C) zone 3 and for skipjack tuna 
(Katsuwonus pelamis) in (D) zone 1, (E) zone 2, and (F) zone 3. The black lines indicate coefficients 
of variation. The vertical black lines indicate standard deviations. 
diet composition among sexes (i?=0.017), size classes 
(i?=0.062), and capture times (i?=0.020), and diet dif¬ 
ferences among months of capture (i?=0.400, P=0.01; 
January =Argonauta spp., Auxis spp., jumbo squid; 
February=jumbo squid; October=Awxis spp., smallwing 
flyingfish [Oxyporhamphus micropterus], Fig. 4). 
Skipjack tuna prey items comprised 7 taxa (1 cepha- 
lopod and 6 fishes). Based on the %MN and %MW indi¬ 
ces, the most important prey items were tropical two- 
wing flyingfish (79.5%; 79.8 %) and smallwing flyingfish 
(4.4%; 5.3%), respectively (Table 6). According to the 
IRI, tropical two-wing flyingfish (96.2%) and smallwing 
