Table 5. — Selected measurements o{ AuxU rochei from five geographic localities (Fitch and Roedel 1963). 



'Matsumoto (1960a) gives 9-15 for 9 western Pacific specimens and 16-18 for 20 from the central Pacific. 

 Roedel's (1963) two central Pacific specimens were from Matsumoto's lot of 20. 



Table 6.— Characters used by several investigators to differentiate Aiucis thazard from A. rochei (Godsil 1954; Fitch and Roedel 

 l%3; Jones and Silas 1964; Yoshida and Nakamura 1965). 



Auxis thazard 



1. Fifteen or more oblique to nearly horizontal dark wa\T lines in 



bare area on each side of back. 



2. Corselet of scales running along lateral line is, at most, three rows 



wide where it passes beneath secimd dorsal. 



3. Pectoral fins extend beyond a vertical from anterior margin of 



patterned bare area on back. 



4. Body compressed from side to side (Fig. 3). 



5. Shape of abdominal cavity more oval. 



6. Right lobe of liver makes a complete loop crossing over mid- 



ventral longitudinal axis (Fig. 41. 



7. Stomach extends to slightly behind anal opening as does right 



lobe of liver. 



8. Caecal mass occupies less space, spleen is smaller, and left lobe 



of liver relatively long. 



9. Temporal crests diverge anteriorly and not parallel with each 



other (Fig. 5). 



10. Skull wide relative to its length (Fig. 6). 



1 1 . Anterior branch of haemal processes long and touching preceding 



haemal arches on 24th to 28th vertebrae (Fig. 7). 



Auxis rochei 



Fifteen or more broad, nearly vertical dark bars on bare area 

 on each side of back. 



Corselet with more than six rows of scales where it passes 

 beneath second dorsal. 



Pectoral fins fail to reach vertical beneath the anterior end of 

 the dorsal bare area. 



Body more rounded and robust . 



Shape of abdominal cavity dorsally compressed. 



Right lobe of liver shows no looping and hepatic vein not in 

 line with midventral longitudinal axis- 



Stomach is short with distal end not reaching anal opening 

 and right lobe of liver extends backward but does not sur- 

 pass a line drawn from origin of anal fin. 



Caecal mass occupies more space, spleen is larger, and left 

 lobe of liver relatively short. 



Temporal crests of skull parallel with each other and supra- 

 occipital crest. 



Skull narrow relative to its length. 



Anterior branch of haemal processes short, fragile, and 

 separated from preceding haemal arches. 



thazard, all 170 specimens of A. rochei fitted into one of 

 three phenotypic protein patterns. They hypothesized 

 that these three phenotypes are controlled by two 

 codominant alleles. Furthermore, the distribution of the 

 three phenotypes was indep)endent of age and sex. 



Almost all proteinases found in animal meat exhibit 

 pH optima in the acid range; however, Makinodan and 

 Ikeda (1969), studying fish muscle protease, concluded 

 that there are actually two types of proteinases in fish 

 muscle — one acting in the acid pH range and the other 

 in the slightly alkaline range. They found that the former 

 occurred in all fish tested whereas the latter was only in 

 fishes with white flesh except the cod, Gadus macro- 

 cephalus. For red or slightly red-flesh fish such as alba- 

 core, Thunnus alalunga; bullet tuna, A. rochei; common 

 mackerel. Scomber japonicus; sardine, Sardinops 

 melanosticta; yellowtail, Seriola quinqueradiata; and 

 horse mackerel, Trachurus japonicus. proteinase activ- 

 ity was either low or not present. 



In attempts to find an easier and faster method of 



identifying larval and postlarval tunas, Matsumoto 

 (1960b) experimented with paper chromatography, an 

 important technique used to identify chemical com- 

 pounds. On the assumption that the free amino acids in 

 the muscle tissues of fishes are hereditary, Matsumoto 

 attempted to separate adult A. thazard from A. rochei 

 but encountered difficulty in distinguishing them; how- 

 ever, he was able to separate the two species from other 

 tunas. 



Sharp and Pirages (1978) inferred the phylogeny of 

 several species in the four tribes of the subfamily Scom- 

 brinae, based on comparison of electrophoretic 

 mobilities of several proteins. Calculating the percent- 

 age of protein bands that are shared and that show 

 similarity between species pairs, they concluded that 

 Euthynnus lineatus is more primitive than A. thazard. 

 Placement of A. thazard above E. lineatus in the 

 phylogeny is supported by the higher affinity of Auxis to 

 both Thunnus albacares and E. lineatus than E. 

 lineatus exhibits to any of the other Thunnini. 



8 



