FOOD OF YELLOWFIN TTJTSTA 



97 



food were found indicating availability." Al- 

 though this final averaged-percentage figure ap- 

 pears to be a combination of dissimilar terms, 

 it perhaps serves as a simplified and useful 

 index. 



Throughout this investigation, as complete rec- 

 ords as possible were kept on the contents of each 

 stomach so that all necessary information would be 

 available for whatever method or methods of 

 analysis were finally decided on. In reviewing 

 the results of the study, it appeared that all 

 three of the basic methods were necessary for 

 proper evaluation of the food of the yellowfin. 

 Therefore, in table 3, which gives the detailed 

 results of the study, there is shown for each food 

 element the total number of such organisms in 

 all stomachs, the number of stomachs in which it 

 occurred, the percent frequency of occurrence, the 

 aggregate total volume of such organisms in all 

 stomachs, and the percent aggregate total volume. 



Regardless of the method of analysis used, there 

 are many uncontrollable variables inherent in 

 food studies which detract from the precision of the 

 results. One may safely conclude, however, that 

 those food items that rank large in number, large 

 in volume, and high in frequency of occurrence are 

 important foods — at the time and in the area 

 sampled. 



Table 3. — Checklist of food organisms found in the stomachs 

 of 1,097 yellowfin tuna captured in the central Pacific, 

 1950 and 1951 



Table 3. — Checklist of food organisms found in the stomachs 

 of 1,097 yellowfin tuna captured in the central Pacific, 

 1950 and 1951 — Continued 



Food organisms 



ARTHROPODA 



Crustacea 



Mysidaeea 

 Oplophoridae: 



Oplophorus foliaceus 



Unidentified mysids 



Amphipoda 



Hyperiidae 



Oxycephalidae 



Qammaridne. 



Caliiopiidae 



Unidentified ampnipods . 



I«opoda 



Ptomatopoda 

 Squillidae: 

 Souilla sp. 



alima 



Pseudotquilla ciliata 



monodactylus stage. . 

 Pseudosquilla oculata 



erichthus 



Lysiosquilla sp. 



erichthus 



Lysiosquilla n. sp. 

 erichthus and post- 

 larvae- 



Gonodaclylus gutreni 

 postlurvae 



Num- 

 ber of 

 organ- 

 isms 



[85, 140] 



20 

 4 



251 



11 



1 



2 



202 

 7 



46 



3,574 

 631 

 315 



81 

 902 



Stomachs in 

 which occurred 



Num- 

 ber 



[734] 



7 

 290 

 112 



114 



34 

 148 



Aggregate total 

 volume 



Percent 



[66. 9] 



.1 

 .2 



7.3 

 .4 

 .1 

 .1 



4.6 

 .3 



.6 

 26.4 

 10.2 

 10.4 



3.1 

 13.5 



Cc. 



[i2,9ni. i; 



105.0 

 .6 



78.0 



2.3 



.2 



.6 



58.3 



1.2 



10.5 



1, 186. 5 



215.3 



152.4 



62.3 



233.6 



Per- 

 cent i 



[24.8] 

 .2 



2.3 

 .4 

 .3 



.1 

 .4 



Food organisms 



Crustacea— Continued 

 Stomaropoda— Continued 

 Squillidae— Continued 

 Odontodactylus hanseni 



postlarvae 



Unidentified stomatopods. 

 Euphausiaeea 

 Eupfaaasiidae: 



Euphausia sp 



Unidentified euphausiids.. 

 Decapoda 

 Penacidac: 



\i tapenaeiu sp 



Unidentified shrimp 



Nepbropsidae: 

 Enoplometopus sp. 



postlarvae 



Palinuridao: 

 Panulirus sp. 

 phyllosoma (larvae). .. 

 put-rulus (postlarvae)-. 

 Unidentified crab larvae 



zoeae 



mpealops 



Paguridie 



Unidentified crustaceans 



MOU.USCA 



pteropoda 



Cavolinidae: 



Carolinia sp 



Unidentified ptcr.. 

 Pectinihranchiata (Hetero- 



Atlantidae- 



id hetCTopods.. 



Decapoda (squid) 



Onychoteuthidae: 



Onyehottuthit nanksi 



Omraastrephidae: 

 Symplectotevtbia ouala- 



nitnsis - 



Octonodoteuthidae 



Unidentified squid 



Octopoda 

 Argonautidae: 



Argonavta titans 



Unidentified argonauts. 

 Bolitaenidae: 



EUdontlla sp 



Unidentified octopods 



1 Given only when 0.1 percent or greater. 



CHORDATA 



Tunicata 



Salpidae: 

 Pyrosuma sp 



Unidentified salps 



Unidentified tunicates 



Vertebrata (Pisces) 



Sternoptychidac (hatchet- 

 flshes) : 

 Sfc rnoptyi diaphava 



Synodidae (lizardfishes)... 



Sudidae 



Alepisauridae (lancet- 

 fishes) 



Lcptownhalus (larvae) 



Myctophidae (lantern- 

 fishes) 



Belonidae (needlefishes) . . 



Hemirhamphidae (half- 

 beaks) 



Exocoettdae (flytneSsbes) 



Macniridae 



Aulostomidae (trumpet- 

 fishes* : 

 Aulostomus chtnensis . .. 



Syngnathidae (pipefishes 

 and seahorses): 



Hippocampus kudo 



Unidentified pipefishes. 



Lophotidae (oarfishes): 

 Lophotes capellei .- 



Holocentridae (squirrel- 

 fishes) 



Num- 

 ber of 

 organ- 

 isms 



1,046 

 164 



35 



18 



2 



75, 875 



4 



99 



[3, M I] 



43 

 1 



3,581 



3 



184 



[240] 



27 



128 



85 



[5,333] 



Stomachs in 

 which occurred 



Num- 

 ber 



142 

 61 



BE 



5 

 12 



2 



529 



1 



39 



2 



51 



[608] 



7 



1 



603 



[69] 



8 

 43 



IS 

 [772] 



Percent 



12.9 

 5.3 



.4 

 7.4 



8.7 



.5 

 1.1 



.2 



48.2 



.1 



3.6 



.2 

 4.6 



[55. 4] 



.6 



.1 



55.0 



.3 

 3.7 



.2 

 2.4 



16 3] 



.7 



[TO 



Aggregate total 

 volume 



Cc. 



446.6 

 105.5 



6.4 

 2.0 



70.0 



2S-. S 



295.0 



2.8 

 16.0 



1.0 



9,363 



.3 



287.0 



5.0 

 1.0 



1.0 



169.2 



[13, 722. 2] 



66.0 



309.0 



700.0 



12, 647. 2 



12.5 



456.6 



45.0 

 176.0 



[300. 0] 



76.0 

 137.2 



86.8 

 [24, 456. 6] 



1.0 

 3.0 

 20.0 



32.0 

 7.2 



79.0 

 52.0 



30.0 



1,740 



2.0 



7.0 



1.0 

 1.5 



15.0 

 6.0 



