white marlin on a year around basis, but the really in- 

 tensive fishing occurs from August through October. 

 The fish start moving into the western coast in July. 

 Schools may be seen off Puerto La Cruz (Distrito 

 Federal), moving east progressively until they reach 

 La Guaira (the port of Caracas) in September (Jaen, 

 1964). 



The seasonal trends in the oceanic longline catches 

 of white marlin differ considerably from those of the 

 inshore sport fisheries. The former are illustrated in 

 Figure 5, on which the following discussion is based. 

 In the North Atlantic, most of the successful fishing in 

 winter occurs off the north coast of South America. In 

 spring, the most productive areas are around the West 

 Indies and the Bahamas, and in the western Carib- 

 bean and the Gulf of Mexico. The latter two areas are 

 the only productive ones in the summer. In early fall, 

 catch rates are high in oceanic waters off the middle 

 Atlantic coast of the United States out to long. 55° W, 

 and also in the Gulf of Mexico. Otherwise there is lit- 

 tle longline fishing success in the fall until catch rates 

 improve in the southeastern Caribbean in Decem- 

 ber. 



In the South Atlantic, the most important longline 

 catches occur from September through February off 

 Brazil. The location and extent of this fishery varies 

 from month to month, gradually shifting southward. 

 There are also scattered areas of high catch rates in 

 various months, expecially spring, in mid-ocean, and 

 another concentration occurs in June-July between 

 lat. 5° and 15°S, long. 5°E, and the African coast. 



5.33 Variations in date or duration of seasons. 



Nothing appears in the literature dealing with 

 variations in the seasons of offshore longline fish- 

 eries. 



Several factors have been noted which contribute to 

 variations in the seasons of some of the sport fisheries. 

 If there were not an accumulation of small forage 

 fishes on which the white marlin could thrive or if the 

 water temperature were not satisfactory, Farrington 

 (1949a) noted white marlin may not occur in the 

 Ocean City area in quantities. Earle (1940) also show- 

 ed that records from the Ocean City fishery show a 

 direct relationship between catches and water 

 temperatures. Nakamura and Rivas (1972) reported 

 that the bluer the water in the South Pass, La., and 

 Northwest, Fla., areas the greater the abundance of 

 white marlin. Current also plays an important role off 

 South Pass. The Loop Current, which comes through 

 the Yucatan Channel up toward South Pass and loops 

 eastward to the De Soto Canyon and down through 

 the Straits of Florida, holds the fish together and 

 brings them right up to South Pass when it is strong, 

 but when it is weak and failing, the fish scatter all 

 over the Gulf of Mexico (H. B. Howcott, pers. com- 

 mun.) The dates and durations of seasons are in- 

 fluenced by the times when these factors become 

 favorable or unfavorable. 



5.4 Fishing Operations and Results 

 5.41 Effort and intensity 



The effort of longline fisheries is easily measured by 

 the number of hooks set, which is usually recorded in 

 thousands. The catch per unit of effort is usually 

 recorded in terms of fish per 100 hooks or per 1,000 

 hooks. In handline or troll fisheries, effort is usually 

 recorded by boat-days, although greater refinement 

 may be achieved by considering boat- or line-hours. 

 The catch per unit of effort is recorded in the terms in 

 which the data are available. 



The effort of Japanese longline vessels in the Atlan- 

 tic, 1956-70, in numbers of hooks fished by years and 

 areas (Fig. 13) is shown in Table 7. These correspond 

 with the catch rates for white marlin shown in Table 

 6. Logbook data for annual fishing effort for the years 

 1956-70 by months and 5° (lat. and long.) quadrangles 

 have been published by Shiohama et al (1965) and the 

 Research Division of the Fisheries Agency of Japan 

 (1965, 1966, 1967a, 1967b, 1968, 1969, 1970, 1971, 

 1972). Factors to adjust these data to estimates for 

 the whole fleet are supplied by Wise and Davis 

 (1973). 



Since comparable data are not available for other 

 longline fisheries, it is difficult to estimate total 

 fishing effort. The Japanese effort reached a peak of 

 nearly 100 million hooks in 1965 and has ranged 

 between about 30 million and 42 million from 1967 

 through 1970. The numbers of Canadian, Japanese, 

 Korean, and Taiwanese vessels which fished in the 

 Atlantic in various years from 1960 through 1971 may 

 give some idea of the relative effort of these fisheries 

 (Miyake and Tibbo, 1972). While the Japanese effort 

 from 1966 through 1970 was well below the 1965 peak, 

 the increased participation of Korean and Taiwanese 

 vessels kept the total effort high in most of those years 

 and the number of Japanese vessels rose sharply in 

 1971. The Canadian fishery, which was for swordfish, 

 Xiphias gladius, and a similar United States fishery, 

 for which we have no effort data, were virtually ter- 

 minated in 1970 because of the discovery of heavy 

 metals in swordfish. Likewise, we have no effort data 

 for Scandinavian longline fisheries, which were 

 primarily directed toward the porbeagle shark, Lam- 

 na nasus, but also caught white marlin like the Cana- 

 dian and United States fisheries (neither country of 

 which marketed this species). 



There are several Latin American commercial 

 fisheries directed toward tunas and billfishes — all of 

 which are marketed in the respective countries. In ad- 

 dition to its local small-boat fishery, Cuba has 4 

 longliners of about 400 gross tons each and 19 of about 

 700 gross tons each (Ferrer Guzman, Carrillo 

 Cardenas, and Jimenez Guerras, 1972). These vessels 

 fish in the tropical Atlantic, the Gulf of Mexico, and 

 the Caribbean Sea. The Venezuelan longline fishery 

 based at Cumana originated in 1959 and leveled off at 

 about 40 vessels of from 20 to 300 gross tons which fish 



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