stomachs of yellowfin and skipjack tunas, had larval 

 copepods and decajxxls in their stomachs (Kishinouye 

 1924). 



Auxis feed on a large variety of fishes, crustaceans, 

 and molluscs. In Auxis captured in Hawaiian waters, 

 fishes comprised the greatest volume with crustaceans 

 next in rank (Tester and Nakamura 1957). Those cap- 

 tured in Japanese waters fed on plankton as well as a 

 wide variety of herringlike fishes such as silverside, 

 Atherina sp.; anchovy, Stolephorus sp.; small round 

 herring, Spratelloides sp.; and immature Engraulis sp. 

 (Kishinouye 1923). Okada (1955) observed that A. 

 rochei fed on small pelagic organisms, anchovies, silver- 

 sides, and other small fishes. Of A. rochei taken in Aus- 

 tralian waters, Whitley (1964) found the stomach cram- 

 med with anchovies and young mullet. 



Auxis also feed on their own young. Yokota et al. 

 (1961) examined A. thazard caught by trolling in 

 Japanese waters in June 1959 and discovered that their 

 diet included young Auxis as well as skipjack tuna. 

 Other items in their diet included jack mackerel, 

 Trachurus japonicus; flyingfishes, Exocoetidae; file- 

 fishes, Monacanthidae; Mene maculata; round herring, 

 Spratelloides japonicus; anchovy; and squids (Table 

 20). 



Troll-caught A. rochei consumed anchovy as the prin- 

 cipal food and other items only infrequently whereas 

 those taken in set nets fed predominantly on jack 

 mackerel with anchovy next in imjxirtance (Yokota et 

 al, 1961). Spotted mackerel. Scomber australasicus. and 



Table 20. — The number of identifiable orgamisms found in stomachs 

 of 30 AuxU thazard caught by trolling gear in Japanese waters 

 (Tokara fishing ground), June 1959 (Yokota et al. 1961). 



Prey 



No. 



Prey 



No. 



Prey 



No. 



Skipjack tuna 9 



Frigate tuna 1 



Jack mackerel 2 



Flyingfishes 



Filefishes 



Ginkagami^ 



1 Kibinago' 

 1 Squid 

 1 Anchovy 



'Kibinago — Spratelloides japonicus (Houttuyn). 

 'Ginkagami — Mene maculata (Bloch). 



lizardfish, Saurida undosquamis, were also found in fair 

 numbers in stomachs of fish caught by set net but were 

 usually absent in stomachs of fish taken bv trolling 

 (Table 21). 



In Indian waters, Thomas and Kumaran (1963) and 

 Kumaran (1964), reporting on the stomach contents of 

 11 juvenile A. thazard (49-132 mm), observed that in 

 small individuals <75 mm, fishes constituted 88"^ and 

 crustaceans 12''c by volume with squids entirely absent 

 (Fig. 30). In individuals >75 mm, fishes formed 39% and 

 Crustacea 42''r by volume. Squids occurred very infre- 

 quently. Anchouiella sp. and Leiognathus sp. were the 



AUXIS THAZARD 

 49-75mm 



AUXIS THAZARD 

 76- 132 mm 



I [ FISH 

 j I CRUSTACEA 

 j j CEPHALOPODA 

 ^H MISCELLANEOUS 



AUXIS ROCHEI 

 170-252 mm 



Figure 30. — Diagrams illustrating the composition, by volume, of 

 the stomach contents of i4uxM thazard and A. Rochei caught in the 

 Indian Ocean (Thomas and Kumaran 1963). 



Table 21.— The stomach contents ot Auxis rochei caught by trolling gear and set net in Japanese waters. 19,'>8-61 (Yokota et al. 1961). 



Date 



Fishing 

 ground 



Num- Spotted Jack Nezumi Kurotachi Sagi- Lizard- Hata- 



ber mackerel mackerel Saury gisu' kamasu" fue^ fish aji' 



Matouishi- 

 mochi 



Mishima- 

 okoze'' Squid Anchovy 



Trolling line: 



Dec. 19.t8 Kumanonada 

 Jan. 19.59 Kumanonada 

 Feb. 1959 Kumanonada 

 Mar. 19.59 Kumanonada 

 Dec. 1960 Kumanonada 

 Jan. 1961 Kumanonada 

 Mar. 1961 Kumanonada 

 Apr. 1961 Kumanonada 



Set or fixed net: 



Apr. 1961 Tanegashima 



Nezumi gisu - Gonor/ivnchu-f aftbrct'iofusTemminckandSchlegel. 



Kurotachi kamasu - Acinaceanot/ia Bor.' and .St. Vincent. 

 Sagifue - Macrorhamphoausscolopax {XJinne). 



'Hataaji - Elephenor macropus iheWolli) . 



Matouishimochi - Apogonichthys carinatus (Cuvier and Valenciennes). 

 Mishimaokoze - Gnat/iagnu«e/ony?a(u-s (Temminck and Schlegel). 



35 



