anglers fishing off Mauritius. Cairns, on the east coast 

 of Australia, is rapidly becoming a very active sport 

 fishing center for blue marlin as well as other species 

 of marlin. An active sport fishery for blue marlin has 

 existed off northern New Zealand for several years. 



5.22 Geographic ranges 



According to data published by Howard and 

 Ueyanagi (1965) and Ueyanagi et al. (1970) the com- 

 mercial longline fishery for blue marlin takes place in 

 the high seas as well as near the coast. The distance 

 from the coast of commercial operations is limited by 

 oceanographic conditions (temperature, depth, etc.) 

 affecting the occurrence of the fish or by restrictions 

 imposed by the various countries. In the sport fishery, 

 the range of the fishery is limited by the range of the 

 boats used by the anglers as well as oceanographic 

 conditions. For example, off Bimini the habitat 

 favorable to the blue marlin is found only 3 or 4 miles 

 from shore. Off Louisiana and northwest Florida, 

 however, blue marlin are usually found not less than 

 40 miles from shore. 



The areas of greatest abundance have already been 

 discussed in 2.1 and 2.3. 



Commercial longline fishing for blue marlin in the 

 Atlantic Ocean developed rapidly from 1958 to 1962 

 (Ueyanagi et al., 1970). After that year commercial 

 fishing operations covered practically the entire dis- 

 tributional area of the blue marlin in the Atlantic. 



The sport fishery for blue marlin has grown steadily 

 since its inception early in this century; growth has 

 been particularly rapid since the end of World War II. 

 Some of the sport fishing areas developed as a result of 

 commercial or exploratory fishing operations. Off 

 South Pass, La., the sport fishery for marlins and 

 tunas started in the midfifties following longline ex- 

 ploratory work by the Bureau of Commercial Fisheries 

 (now National Marine Fisheries Service) (Bullis, 

 1955; Captiva, 1955). 



5.23 Depth ranges 

 No information available. 



5.24 Conditions of the grounds 

 No information available. 



5.3 Fishing Seasons 



5.31 General pattern of seasons 



The fishing seasons vary according to the seasonal 

 movements of the fish as discussed in 2.1 and 3.51. 



5.32 Dates of beginning, peak, and end of 

 season 



In the commercial fishery the longline fleets can 

 follow the seasonal movements of the fish; however, 



this is not true for the sport fishery. For example, in 

 the northern Gulf of Mexico the sport fishing season 

 begins in April or May, reaches a peak in July and 

 August, and ends in October or November (Nakamura 

 and Rivas, 1972). On the other hand, in tropical areas 

 such as Puerto Rico and Jamaica, sport fishing for the 

 blue marlin is conducted throughout the year. 



5.33 Variation in date or duration of season 



As discussed above in 5.32, the off-season for the 

 sport fishery in the northern Gulf of Mexico is from 

 November to April. During that period adverse 

 weather conditions prevent sport fishing boats from 

 venturing out. Furthermore, low water temperatures 

 render the habitat unsuitable to the blue marlin. The 

 same applies to the sport fishery in areas with a 

 similar climate. 



5.4 Fishing Operations and Results 



5.41 Effort and intensity 



In the longline fishery the unit of effort is the 

 number-of-fish-per-hundred-hooks. In the sport 

 fishery the same unit of effort may be used, but 

 Nakamura and Rivas (1972) have suggested that 

 number-of-fish-raised-per-hour-of-trolling may be a 

 better index of relative abundance. 



Ueyanagi et al. (1970) have given the monthly 

 change of the mean hook-rate by area for the blue 

 marlin in the Atlantic Ocean during 1956 through 

 1965. 



In the commercial longline fishery the causes of 

 variation in fishing effort are the result of changes in 

 economic factors and fluctuations in stock abun- 

 dance. In the sport fishery, weekends, national 

 holidays, and traditional summer vacations are 

 causes of variation in fishing intensity. In general, 

 fishing intensity is highest on weekends. In certain 

 areas, such as the northern Gulf of Mexico, sport 

 fishing intensity drops markedly during the Labor 

 Day weekend. Presumably, anglers select that par- 

 ticular holiday to spend time with their families 

 before the children go back to school. However, in 

 areas such as southern California this is the period 

 when the peak fishing effort for billfish occurs. 



5.42 Selectivity 



The longline is selective for larger fish and in the 

 sport fishery the baits are rigged to catch the larger 

 fish. Anglers and fishing guides believe that the larger 

 the bait and the hook, within limits, the larger the 

 blue marlin that the bait will attract. This is the rule 

 only in certain areas. Off South Pass, La., anglers troll 

 mostly large baits with a corresponding large hook. 

 They specialize almost exclusively in blue marlin 

 fishing and usually catch more of them (number-of- 

 fish-per-hour-of-trolling) as compared to northwest 



13 



