DRAGOVICH and POTTHOFF: FOOD OF SKIPJACK AND YELLOWFIN TUNAS 



this study were caught by pole and line or by 

 trolling (Table 1) . A total of 711 stomachs from 

 skipjack tuna and 132 from yellowfin tuna were 

 examined. The skipjack tuna studied varied in 

 fork length from 36 to 63 cm and the yellowfin 

 tuna from 52 to 94 cm (Figure 2), 



Sampling of catches for stomach samples was 



carried out as other requirements of the program 

 and circumstances permitted. Immediately 

 after completion of the morphometric work 

 aboard the ship the stomachs were removed by 

 opening the abdominal cavity and by severing 

 them from the intestine and the esophagus. Each 

 stomach was pierced in several places to allow 



Table 1. — Distribution of skipjack and yellowfin tuna stomachs collected during 1968 from the eastern tropical 



Atlantic Ocean, identified by month, cruise, and method of capture. 



1 UN68CI) = RV Undaunted 6831 cruise. 



2 UN68a2 = RV Undaunted 6832 cruise. 



SKIPJACK 



z 



HI 



UJ 

 Q. 

 (/) 



u. 



O 70 



cc 



UJ '0- 

 OQ 



S so 



Z 40 



30 

 JO- 

 10- 



YELLOWFIN 



UN-6801 

 N=431 



UN-6801 

 N=84 



39 41 43 45 47 49 SI S3 5S 57 59 



52 54 56 51 to 62 64 66 61 70 72 74 ^ IS 



UN-6802 

 N=280 



''^T■ 



3t 40 42 44 46 41 50 52 S4 56 St 60 62 



63 65 67 69 71 73 75 77 79 «1 «3 IS 87 19 91 93 



FORK LENGTH (cm) 



Figure 2. — Length-frequency distribution of skipjack tuna and yellowfin tunas from which stomachs were collected. 



1089 



