I am unaware of any specific reasons why 

 this fishery cannot be expected to produce 

 more. 



With respect to various other areas 

 and species, longline yellowfin in the 

 Western Pacific are decreasing somewhat and 

 are likewise decreasing in the Central 

 Pacific. However, there is no evidence of 

 decline in the albacore taken by longline 

 fisheries in the South Pacific. In the 

 Indian Ocean, longline yellowfin have de- 

 creased markedly as to catch per hundred 

 hooks. Albacore production has become 

 more important than it was during the 

 initial exploitation of this oceanj reports 

 indicate that there have been some import- 

 ant catches of bluefin. The Atlantic Ocean 

 is just coming into heavy production and 

 there is some limited evidence that a de- 

 crease in catch per hundred hooks is 

 occurring. 



Based on the various historic trends, 

 longline yellowfin can be expected to be 

 reduced to roughly three fish per hundred 

 hooks in most of the world within a few 

 short years. Bigeye, albacore and bluefin 

 have not declined nor has skipjack. 



CONCLUSIONS 



The world tuna fishery was enormously 

 stimulated in the years after World War II 

 and almost every tuna producing country in 

 the world has significantly increased its 

 catch in the past decade, by far the domin- 

 ant tuna-producing country in the world is 

 Japan, and the most important factor in 

 Japanese production is the expansion of her 

 longline fisheries. In turn, the Japanese 

 longline fisheries have depended heavily on 

 yellowfin tuna and catch rates for this 

 species have had a tendency to decline 

 sharply after the initial exploitation of 

 virgin grounds. The decline in yellowfin 

 catch rate is still being offset by devel- 

 opment of new fishing areas. While the 

 decline in catch rate may ultimately be a 

 problem to the Japanese it emphasized that 

 their fishing depends on a number of species 

 of tuna and on other fishes as well. The 

 continued importance of Japan as a competi- 

 tor for American fishermen and supplier of 

 tuna for world markets is likely. The Jap- 

 anese overseas operations appear to be an 

 important hedge on operational cost trends 

 and doubtless contribute to the strength of 

 the Japanese fisheries. The various tuna 



populations (except yellowfin in the East- 

 ern Pacific) appear to be capable of pro- 

 ducing more heavily. In general, the tuna- 

 producing countries of the world can be 

 expected to continue to increase their 

 fisheries and tuna harvest as long as their 

 fisheries are profitable. 



ACKNOWLEDGEMENT 



This report was developed with major 

 assistance from the Bureau's Biological 

 Laboratory, Honolulu and Branch of Special 

 Reports, Washington, D. C. The statistical 

 data by country, which was assembled by the 

 latter unit arose from a variety of sources 

 as follows: 



Japan . Data for 1953 and 1957 from the 

 Japanese Government's Annual Reports 

 on Fishery and Agriculture, 195U and 

 1957. Data for 19U8 were obtained 

 from the Statistical Abstract of the 

 Ministry of Agriculture and Forestry, 

 1957. 



United States . The primary source of 

 information was Fishery Statistics of 

 the United States, 19U8, 1953, and 1957. 



Peru . Data for 1957 were derived from 

 the Annual Statistical Fishery Report, 

 Peru, 1957' This was received as 

 Dispatch No. U36 of the U. S. Embassy, 

 Lima, dated October 30, 1958. 



Taiwan . Data for 19U3 were obtained 

 from the Taiwan Agricultural Yearbook, 

 1950 edition. All other information 

 was taken from the United Nations, 

 Food and Agriculture Organization Tear- 

 book of Fishery Statistics, Vol. VII, 

 1957, Rome. 



The Honolulu Biological Laboratory 

 received assistance from Japanese scientists, 

 which is mentioned in the text and is grate- 

 fully acknowledged. 



LITERATURE CITED 



Anonymous 



1959 First Atlantic Tuna Long-Liner 

 Returns to Home Port. Commercial 

 Fisheries Review , vol. 21, no. 2, p. 61. 



Anonymous 



1959b Japanese Fisheries Based in 

 Overseas Areas. Fishery Leaflet I$5, 



34 



