Indian Ocean to the north of lat. 20°S was virtually 

 covered. Since then, the grounds have spread 

 southward, with albacore in waters off Madagascar 

 as the primary objective. In the eastern Indian 

 Ocean the fishery spread southward in pursuit of the 

 southern bluefin tuna, and by 1964, reached lat. 

 40°S. The distributional range of the several species 

 of billfishes was completely covered at this time. 

 Southerly movements since 1964 were related to 

 southern bluefin tuna exclusively, and not to bill- 

 fishes. 



Atlantic Ocean 



The longline fishery in the Atlantic Ocean began 

 in 1956 (Fig. 6) in waters north of Brazil for yellowfin 

 tuna. Within 2 or 3 years it expanded in equatorial 

 waters to the African coast. 



Since 1958 the fishery has spread both to the north 

 and south in pursuit of albacore, and by 1965, had 

 covered the area between lat. 45°N and 45°S. It then 

 became continuous with the Indian Ocean grounds 

 by moving around the southern tip of Africa. In the 

 Atlantic, as in the Pacific and Indian Oceans, the 

 fishing grounds cover the entire distributional range 

 of the billfishes. 



In summary, it is seen that by 1965 virtually the 

 entire distributional range of billfishes in the Pacific, 

 Indian, and Atlantic Oceans had been covered by the 

 Japanese longline fishery. In this regard, it can be 

 said that with this coverage it has become possible to 

 view the entire distributional picture of the billfishes 

 through the activities of the longline vessels. 



THE DISTRIBUTION OF FISHING 



EFFORT AND THE CATCH 



OF BILLFISHES BY THE JAPANESE 



LONGLINE FISHERY 6 



The distribution of fishing effort of the Japanese 

 longline fishery, in terms of numbers of hooks 

 fished, has been plotted for 1970 by 5° quadrangles 

 (Fig. 7). It is seen that fishing effort was particularly 

 large in such areas as the northwestern Pacific, 

 equatorial Pacific, and certain areas around lat. 

 40°S, especially south of Australia and around New 

 Zealand. If fishing effort of the vessels from Taiwan 

 and South Korea is included, it will show considera- 



6 Data source from Fisheries Agency (of Japan), 1972. 



ble effort in all oceans, particularly in the equatorial 

 regions. 



Although the fishing effort is aimed principally at 

 the tuna resources, there are areas where the effort is 

 primarily for certain species of billfishes. 



Fishing effort for albacore, bigeye tuna, striped 

 marlin and swordfish is concentrated in the north- 

 western Pacific, that for bigeye tuna and striped 

 marlin in the northeastern Pacific. In the central 

 equatorial Pacific region effort is concentrated on 

 yellowfin tuna and bigeye tuna as well as the blue 

 marlin. Bigeye tuna and striped marlin are the prin- 

 cipal species sought in the eastern equatorial region. 

 In Mexican waters the effort is exclusively for 

 striped marlin, and such exclusive fishing effort for 

 billfish is seen nowhere else, except for sailfish in the 

 coastal waters of Central America. 



In waters south of Australia fishing effort is con- 

 centrated on the southern bluefin tuna. 



The 1970 catch of striped marlin (Fig. 8), and blue 

 marlin (Fig. 9), in numbers, is shown by 5° quad- 

 rangles. The striped marlin catches are relatively 

 high in the central North Pacific and in the eastern 

 Pacific. Other areas of good catches are in the wa- 

 ters east of Australia, northwest of Australia, Bay 

 of Bengal, and the Arabian Sea. There are also 

 some good catches in the western North Pacific. 



As for the blue marlin (Fig. 9), the areas of good 

 catches range from the western equatorial to the 

 central equatorial Pacific Ocean. 



THE HARPOON FISHERY 



Although the harpoon fishery primarily seeks bill- 

 fishes, the catch is very small compared to that made 

 by the longline fishery. The catch of Japan's harpoon 

 fishery in 1970 was approximately 3,000 tons of bill- 

 fishes, or less than 5% of the total Japanese billfish 

 landings. 



The vessels of the harpoon fishery are of wooden 

 construction and range in size from about 10 to 40 

 tons. All catches made by these vessels are iced for 

 delivery to the markets. Because of shorter trips, the 

 fish are relatively fresh when landed and thus com- 

 mand good prices at the market. The fish are suitable 

 for use as sashimi. 



The harpoon fishery operates in coastal waters, 

 and in Japan, takes largely the striped marlin and 

 swordfish. The fishing grounds are located in waters 

 off Sanriku (northeastern Honshu), around Izu Is- 

 land, and in the East China Sea. The seasons are 

 from July through October in the Sanriku grounds. 



