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I. DESCRIPTION OF THE FISHERY 

 I. A. History of the Fishery 



The bill fishes (blue marl in, Makaira nigricans , striped marl in, 

 Tetrapturus audax , black marl in, M. indica , swordfish, Xiphias gladius . 

 sail fish, Istiophorus platypterus . and shortbill spearfish, T. 

 angustirostris ) are widely distributed and have generally similar 

 distributions in the Indian Ocean (Figure 1). Bill fishes are caught only 

 incidentally by longliners because the target species in the Indian Ocean 

 are the various tunas. Major participating fleets include those of Japan, 

 Taiwan, and Korea, although Tanzania and the U.S.S.R. also report billfish 

 catches from the Indian Ocean to the FAO (Food and Agriculture Organization 

 of the United Nations 1977). Indonesian vessels and sport fishermen in 

 South Africa, Kenya, Seychelles, and western Australia probably catch a 

 small amount of bill fishes. 



According to Ueyanagi (1974), the Japanese longline fishery around 

 the Lesser Sunda Islands began expanding into the Indian Ocean in 1952 

 (Figure 2), By 1956, Japanese vessels were fishing in African coastal 

 waters and by 1958, they had reached the northern limit of the Indian 

 Ocean. Subsequent expansion was southward. By 1964, longline operations 

 had reached 40° S latitude, the southern limit of billfish distribution. 

 Further southward expansion was solely for the southern bluefin tuna. 

 Longline boats of Taiwan and Korea began fishing in the Indian Ocean in 

 1954 and 1967, respectively (Honma and Suzuki 1972). 



I.B. Trends in Catch and Effort 



The estimated total billfish catch from the Indian Ocean amounted 

 to 7,804 mt (metric tons) in 1975 and 7,062 mt in 1976 (Wetherall et al.M. 

 The catch is listed by species, country, and year in Table 1. Data for 

 catch, relative abundance, and effective effort are available from 1952 to 

 1976 (Table 2). 



Wetherall, J. A., F. V. Riggs, and M. Y. Y. Yong. 1979. Some produc- 

 tion model analyses of tuna and billfish stocks in the Indian Ocean. 

 SWFC Admin. Rep. H-79-7, Natl. Mar. Fish. Serv., NOAA, Honolulu, Hawaii, 

 12 p. Prepared for the Workshop on the Assessment of Selected Tunas and 

 Billfish Stocks in the Indian and Pacific Oceans, Shimizu, Japan, 13-22 

 June 1979. 



