MATHER, JONES and BEARDSLEY: MARLINS IN ATLANTIC 



Figure 4. — Location of releases and recaptures of white 

 marlin tagged in the western North Atlantic Ocean south 

 of lat 32 °N. The months of release and recapture are 

 shown in that order for each return. The number of 

 recaptures at each site (if more than 1) is indicated 

 in parentheses. 



migratory pattern, but the remaining five do not. 

 We do not now understand the relation between 

 the nearly simultaneous summer and early fall 

 concentrations of white marlin off the U.S. east 

 coast and in the northern Gulf of Mexico. An 

 interchange of fish between these two areas has 

 not been demonstrated. None of the white mar- 

 lin released in the Gulf of Mexico have been re- 

 captured elsewhere, but a white marlin tagged 

 in the Straits of Florida in January was recap- 

 tured in the Gulf of Mexico the following July. 

 This recapture indicates that white marlin 

 found off the northwestern Bahamas in winter 

 may be a component of the summer concentra- 

 tion in the Gulf of Mexico. If this indication 

 is correct, white marlin from the Bahamas could 

 be migrating westward through the Straits of 

 Florida while others en route to the U.S. middle 

 Atlantic coast from the Caribbean are passing 

 through the Straits to the east. White marlin 

 are caught throughout the winter in the Baha- 

 mas, but fish tagged off Cape May-Cape Hatteras 

 appear to migrate through the region only from 

 early April to mid-July. 



Tag returns indicate that white marlin off 

 Venezuela in August and September remain off 

 the north coast of South America into November 

 and December, and that they are then joined 

 by fish from the U.S. middle Atlantic coast. 

 We are not sure how the marlin in the summer 

 and early fall concentration off Venezuela are 

 otherwise related to those in the summer and 

 early fall concentrations in the Gulf of Mexico 

 and off the U.S. middle Atlantic coast. 



Early opinions that white marlin and other 

 billfishes are short-lived and grow rapidly (Voss, 

 1956) are apparently true for Atlantic sailfish, 

 Istiophorus platypterus (de Sylva, 1957), but 

 de Sylva and Davis (1963) pointed out that 

 white marlin may be long-lived. Their opinion 

 was based on the weight-frequency distributions 

 of fish in the U.S. sport fishery and the recovery 

 of a tagged fish which had been at liberty for 

 4 years (Mather, 1960). The more recent in- 

 formation gained from tagging supports the be- 

 lief of de Sylva and Davis (1963). Six tagged 

 white marlin have been recaptured after 3 to 4 

 years at liberty. A comparison of sizes at re- 

 lease (estimated) and recapture does not indi- 

 cate rapid growth after recruitment into the 

 fishery. 



We estimated the mortality rate of white mar- 

 lin from tag-return data, using returns from 

 white marlin tagged north of lat 32 °N only 

 (most fish were tagged in this area; those 

 tagged in other areas might have had different 

 migratory patterns). Moreover, we confined 

 our consideration to returns from fish tagged in 

 1961 through 1965, because only two fish tagged 

 before 1961 were recaptured and because re- 

 turns from fish tagged after 1965 were incom- 

 plete. When the data were platted from white 

 marlin recaptured from less than 1 month to 

 more than 48 months after tagging, the recovery 

 rates approximated an exponential relationship. 

 The tag returns were grouped into time periods 

 such as 0-12 months and 12-24 months, in view 

 of a preliminary analysis which indicated that 

 the returns within the first 6 months were in 

 accord with the general pattern of returns 



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