Table 4. — Releases (after slash) and returns (before slash) for blue marlin tagged in the western North Atlantic Ocean by 



year and area of release. 



'Through 20 July. 



39% in the earlier calculation). These results sup- 

 port our belief that the returns do have biological 

 significance. These relatively low mortality rates 

 are further indications of the longevity of the 

 species. They also show that released white marlin 

 have a fair chance of continued reproduction, and 

 of being available to fisheries for an appreciable 

 period. 



BLUE MARLIN 



New information on migrations of blue marlin is 

 limited to one valid return^ and one for which the 

 release data are uncertain (Table 4, Fig. 6, Appen- 

 dix Table 5). The valid return shows a migration 

 from the northwestern Bahamas in February 1969, 

 to the central Gulf of Mexico in August 1971. Simi- 



lar migrations have been noted in this report and by 

 Mather et ai. (1972) for white martin, and by 

 Mather, Tabb, Mason, and Clark (1974) for sailfish. 



'Another tag from a blue marim was returned after this man- 

 uscript was completed. This fish was released near Walkers Cay 

 (northern tip of the Bahamas) in July 1971, and recaptured off 

 Elbow Cay. Cay Sal Bank, Straits of Florida, in July 1972. Its 

 weight was estimated at 68 kg when released, and it weighed 86 

 kg when recaptured. 



to 



i 



o 



to 



tt 

 til 

 I 



0-12 12-24 24-36 36-48 48-60 



MONTHS AT LIBERTY 



Figure 5. — Number of returns from white marlin tagged 

 in 1961-67 in waters north of lat. 33°N, plotted by time at 

 liberty. 



219 



