THE SHORE FISHES OF PERU 371 



Although the 610 fish measured by the Mission ranged in length from 

 490 to 1,200 mm., most of them were 650 to 770 mm. long. 



The Mission (1943, p. 229) reported that the fish are taken com- 

 mercially by trolling. The investigators were successful in catching 

 the fish, also, from the stern of the vessel by using short stout poles, 

 "rigged with a short line and a feather jig." This equipment is 

 commonly used by tuna fishermen when schools of fish have been 

 brought near with bait. Stomachs examined aboard the trawler 

 contained chiefly anchovies, squids, small mackerel, and silversides 

 (pejerreys). 



The report of the Mission (1943, p. 23) has stated that this tuna is 

 known as "albacora" in northern Peru and as "atiin" and "tuno" in 

 central and southern Peru. This difference in names in itself is con- 

 fusing and the confusion is greatly increased by the use of "albacora" 

 for the swordfish, Xiphias gladius, in central and southern Peru. 



It seems that Jordan and Hubbs (1925, p. 219) believed the presence 

 or absence of black on the finlets was significant. Schlegel's original 

 plate (see reference above) does not show any black on the finlets, 

 and Kishinouye's plate (see reference above) also fails to show it. 

 However, all the specimens from Peru have the finlets prominently 

 marked with black, as stated in the description. The black is in- 

 dicated in Walford's plate (see reference above), though not promi- 

 nently. In the number of gill rakers, fin rays, and finlets the Peruvian 

 specimens agree with Japanese fish, as given for the latter by Kishi- 

 nouye. 



Nichols and LaMonte (see reference above) have stated that the 

 Atlantic and Pacific yellowfin tunas are of the same species, and 

 have united them under Neoihunnus alhacora (Lowe). It is not 

 evident from the publication that these authors compared specimens, 

 or accurate data based on specimens, from the two oceans, which 

 in my opinion is necessary to prove their identity. Photographs 

 have often been used by authors in classifying tunas. Consequently 

 accurate enumerations of fin rays, gill rakers, and proportions are 

 largely missing. Presumably because the relative length of the dorsal 

 and anal lobes could be more or less definitely determined from photo- 

 graphs, this character has received considerable attention. How- 

 ever, Kishinouye (1923, p. 446), Herre (1936, p. 106), and Walford 

 (1937, p. 3), all of whom examined many specimens of yellowfin tuna, 

 agree that the character is virtually useless because of the great varia- 

 tion in development among individuals. As the lobes become elon- 

 gated only v/hen the fish attain a large size it is not usable, in any 

 event, in identifying the smaller individuals. For reasons stated, I 

 regard the classification of T. macropterus and its relatives unsettled. 

 Although I am assigning the Peruvian material to T. macropterus, 



