In spite of the tremendous amount of at- 

 tention given the tunas in recent years, the basic 

 problems of taxonomy and nomenclature are still 

 unresolved. Several things have contributed to 

 this; for example, many of the past descriptions 

 are too brief, the localities of capture are often 

 vague, and the taxonomy of the group is often 

 approached from a geographically narrow point 

 of view. As a result, a multitude of names ex- 

 ist for fish which could well be of the same spe- 

 cies but were simply taken in different parts of 

 an ocean or indifferent oceans. To further com- 

 plicate matters there are today two schools of 

 thought among taxonomists with regard to the 

 tunas: (1) those who recognize the existence of 

 numerous species indifferent parts of the world 

 and (2) those who contend that there are only a 

 few species widely distributed throughout the 

 world. 



The purpose of the open discussion was 

 to identify the various problems concerning the 

 taxonomy of the tunas and to find solutions to 

 these problems or decide upon the best means 

 by which they could be solved. 



Several problems, two in the form 

 of questions, were brought out during the 

 discussion: 



1. How many genera are there among 

 the tunas ? 



2. How many species comprise the 

 tuna? 



3. Difficulty in defining genus . 



1. It was pointed out and generally ac- 

 cepted that there is no reason to split the tunas 

 taxonomically to the point where each species is 

 given a generic name. This means that such ge- 

 neric names as Parathunnus , Neothunnus, and 

 Kishinoella should be replaced by Thunnus. 

 Other genera (Euthynnus, Katsuwonus, and Auxis) 

 were not discussed. 



2. The single -species concept was 

 strongly advocated for yellowfin, bigeye, alba- 

 core, and skipjack. It was also felt that T. 

 tonggol and T. atlanticus are valid species . One 

 exception to this single -species concept was 

 pointed out in the bluefins. The Pacific T_. 

 orientalis and the Atlantic T. th_ynnus were sug- 

 gested to be subspecies on the basis of gillraker 

 counts. Here again, species of two other genera, 

 Euthynnus and Auxis , were not discussed. 



3. While it was clearly recognized that 

 the problem is extremely subjective and, there- 

 fore, difficult for researchers to come to any 

 agreement on, it was pointed out that some de- 

 gree of objectivity was possible in taxonomic 

 works. Inthecaseof species there may be evi- 

 dence of reproductive isolation. The use of se- 

 rology in separating tunas on the generic level 

 was suggested. It was felt that this technique 

 has some possibility, even though the problem 

 is not solvable at this time. 



Although there was general agreement 

 on the greater portion of the species and genera 

 discussed, evidence of some reservations was 

 clearly displayed when suggestions for carrying 

 out further work in clarifying the taxonomic 

 problem were offered. The consensus was to 

 appoint a well -qualified person or committee to 

 prepare a thorough background paper for the 

 FAO World Tuna Conference and to determine 

 whether or not there is need for more data. 



In connection with the need for more 

 data, Hiroshi Nakamura kindly offered his co- 

 operation in collecting specimens of various spe - 

 cies of tunas from all oceans of the world in 

 which Japanese fishing operations are being 

 carried on at the present time. 



At this point, with further work to be 

 done on some of the problems and in order to 

 formulate recommendations wherever needed, a 

 working group was appointed consisting of 

 Phil M. Roedel, Chairman, John C. Marr, 

 Hiroshi Nakamura, and Robert H. Gibbs, Jr. 



Distribution 



Discussion Leader - Donald W. Strasburg 

 Rapporteur - Robert T. B. Iversen 



Reference: Papers No. 



I - 1. Nakamura, H. - An outline of the tuna longline grounds in the Pacific 



2. Kamimura, T., and M. Honma - Distribution of yellowfin in the longline fishing 

 ground in the Pacific Ocean, especially on the regional variation of the density 

 in each size group 



