CLASSIFICATION 



1. general 



The pelagic epeciee dlBcaesed in this paper are memhers of two orders of fisheei 

 the Scombri formes and the Xlphilformes. Despite the fact that the majority of the species 

 are well known to the layman and have heen fished intensively In many parts of the world 

 for hoth sport and commercial purposes, their claself ication is still unsettled. The huge 

 size of many of the species prevents museums from preserving specimens, and scientific work- 

 ers have been unable to obtain adequate material from different regions for comparison. 



A brief outline of the generally accepted major families within each of the two 

 orders Is presented below merely to orient the reader, as it is not within the scope of this 

 paper to discuss either classification or nomenclature. Hepresentative species in each fam- 

 ily are glveni followed by widely used Snglish and Japanese common names. The species mark- 

 ed with an asterisk are the commercially important Japanese oceanic forms. 



Order SCOMBRIFOBJtEo 



yamlly Scombrldae (mackerels: saba) 



Scomber Japonicus (common mackerel: honsabai maeaba) 

 Family Katsuwonldae (small tunas: katsuo) 



• KatsuwonuB pelamis (skipjack: katsuo) 

 ButhynnuB yaito (mackerel tuna: yaito) 



Auxie tapelnosoma (frigate mackerel; marusoda) 

 Family Thunnldae (tunas: maguro) 



• Thunnus orl entails (black tuna: kuromaguro) 



• ThunnuB germo (albacore: blncho) 



• Parathunngg mabachl (big-eyed tuna: mebachl ) 



• Meothunnua macropterue (yellowfin tuna: ki hadamaguro ) 

 Family Cybiidae (seer-fiBhee: sawara) 



Sawara nlphonia (Spanish mackerel: sawara) 

 Sarda oriontalis (oriental bonlto: hagatsuo) 



Order XIPHIIFOEMES 



Family Istiophoridae (sailflsh and marllns: kajikl) 



• Makalra mi t sukuri i (striped marlln: makajikl) 



• Makal ra mazara (black marllns kurokajlki) 



• kakaira inarllna (white marlln: shlrokajiki) 



• Istiophorus orientalie (sailflsh: bashokajikl) 

 Family Xlphildae (swordfish: kaJlkl) 



• Xlphlas gladiUB (broadbill swordfish: mekajikl) 



The Bcombrlform fishes are characterized by a series of finlets which extend from 

 the dorsal and anal fins back to the base of the caudal fin. On the sides of the caudal 

 region they possess two or three pairs of lateral fleshy outgrowths which act as keels. 

 All scombroid fishes are remarkably streamlined, with the forward fins (pectorals, pelvics. 

 and first dorsal) fitting into grooves or slots when they are folded. bv>t perfect stream- 

 lining is more nearly attained in the plump spindle-like form characteristic of the truly 

 oceanic types. The scombroids include species that are primarily coastal In their habitat 

 preference (for exaiqple. the common mackerel and the Spemlsh mackerel). However, the more 

 spectacular species are those that attain gigantic sizes. They are inhabitants of the off- 

 chore pelagic waters, although several species, notably the skipjack and the black tuna. 

 enter shallow coastal waters In considerable numbers, apparently for the purpose of feeding. 

 These offshore forms, together with the xiphllforms (discussed below), are the species that 

 support the Japanese tuna fisheries. 



The zlphliforms possess an upper Jaw prolonged into a spear or sword composed of 

 consolidated bone. The body, like that of the mackerel fishes. Is streeunllned. and, here 

 too. the forward fins fit Into grooves or slots. One ar two pairs of lateral keels are 



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P-6307 



