northern tip of the Bahamas (Farrington, 1937, 1949a, 

 1949b; Hemingway, 1949; Migdalski, 1958; Brooks, 

 1968). This period is also the most productive for sport 

 fishing for white marlin off southeastern Florida, 

 Puerto Rico (Erdman, 1957), and the Virgin Islands. 



White marlin apparently are less abundant in the 

 eastern North Atlantic and the Mediterranean, but 

 have been recorded occasionally in those waters. 

 LaMonte (1955) reports catches off "Portugal, Azores 

 Islands, Madeira, and the Italian Riviera." Legendre 

 (1928) and Desbrosses (1938) reported single captures 

 of T. belone and T. Lessonae, respectively, both taken 

 in September from tuna fishing boats well off Brittany 

 (west of the entrance to the English Channel and "200 

 miles from Groix," respectively). Both records have 

 been placed in the synonymy of T. albidus (LaMonte, 

 1955). Rodriguez-Roda and Howard (1962) reported 

 on 19 specimens of white marlin captured off the 

 southern coasts of Portugal and Spain in 1961 — 16 in 

 August, 1 in September, and 2 in October. Thirteen of 

 these captures were in the Atlantic, 2 in the Strait of 

 Gibraltar, and 4 at La Linea, Spain, just inside the 

 Mediterranean Sea. Robins (1974) lists 37 specimens 

 caught off southern Portugal in late July and August 

 1961, and 2, observed by Mather, which were caught 

 off Cadiz, Spain, on 6 October 1969. Twenty-three of 

 these fish were caught by hook and line (most, if not 

 all, by longline), and 35 by tuna traps (almadrabas). 

 Furnestin et al. (1958) describe two specimens taken 

 off Morocco, one by longline off Mazagan, August 

 1950, and one by trawl net off Casablanca, July 1953, 

 and state that the species is taken very frequently by 

 longline off Tangier and in the vicinity of Casablanca. 

 A photograph (Lozano Cabo, 1958, Fig. 93) of a fish 

 caught in a tuna trap at Ceuta, Spain (African coast, 

 just inside the Mediterranean) is captioned and 

 referred to as T. belone, but we concur with Robins 

 and de Sylva, 1960, in re-identifying this fish as T. 

 albidus. This information indicates that white marlin 

 are fairly abundant in the Atlantic approaches to the 

 Mediterranean in August and September, and oc- 

 casionally enter the western part of the Alboran Sea. 



Records of T. albidus in the remainder of the 

 Mediterranean, however, are very scarce. Tortonese 

 (1940, 1961, 1962, 1970) re-identified two mounted 

 specimens, which had been caught near Genoa, Italy, 

 in the nineteenth century, as T. albidus and reported 

 the capture of two others in a small tuna trap 23 km 

 east of that city in September 1970. In his opinion, the 

 species occurs only in the western part of the 

 Mediterranean, and is very rare there. Cesareo (1967) 

 recorded the harpooning of a white marlin in 

 September 1967, near the Island of Gallinara in the 

 Ligurian Sea. Sara (1968) noted that T. albidus con- 

 tributed to the catches of some Sicilian tuna traps, 

 and Bini (1968) (not seen by us, but quoted by Tor- 

 tonese, 1970), also stated that this species occurs in 

 Sicilian waters. 



Annual variations in distribution are most notable 



in areas where the distribution is seasonal, especially 

 near the limits of the range of the species. These 

 variations are usually attributable to one or more of 

 the determinants of distribution changes (see 2.3). 



2.3 Determinants of Distributional Changes 



The distribution of white marlin is controlled 

 primarily by the necessities of feeding and spawning, 

 and secondarily by conditions of the environment. 



The spawning areas of white marlin have not been 

 completely defined, but it appears that some coastal 

 concentrations (Bahamas [de Sylva and Davis, 1963; 

 Stephens, 1965], Cuba, and the Greater Antilles 

 [Erdman, 1956] ) are related to spawning, while others 

 (northern Gulf of Mexico [Gibbs, 1957], Cape 

 Hatteras-Cape Cod [de Sylva and Davis, 1963], 

 Venezuela [Jaen, 1964], and outside the Strait of 

 Gibraltar [Robins, 1974]) are related to feeding. The 

 latter are all in areas of relatively high productiv- 

 ity. 



It also appears that the oceanic concentration off 

 southern Brazil is a spawning assembly (Hayasi et al., 

 1970). 



Water temperature appears to exert an important 

 influence on the distribution of white marlin. Gibbs 

 (1957) related the monthly changes in the distribution 

 of white marlin catches in the Gulf of Mexico to the 

 position of the 75°F (23.9°C) isotherm. Ovchinnikov 

 (1970) stated that a temperature of 24° C is optimal 

 for white marlin. Squire (1962) showed that at ex- 

 ploratory longline stations where white marlin were 

 caught by MV Delaware and RV Crawford in the 

 western North Atlantic, surface temperatures ranged 

 from 70.0° to 83.0°F (21.1° to 28.3°C), with a 

 weighted average of 76.6°F (24.8°C), and 

 temperatures at the estimated fishing depth 

 (estimated as 173 feet or 52.7 m) ranged from 50.0° to 

 80.5°F (10° to 27°C), with a weighted average of 

 68.8°F (20.5°C). De Sylva and Davis (1963) showed, 

 from extensive observations taken of southern New 

 Jersey and Maryland during the summer of 1959, that 

 the white marlin grounds were generally characterized 

 by surface water temperatures between 78° and 80°F 

 (25.6° and 26.7°C). Most of the longline catches of 

 white marlin have been on the warm side of the 20°C 

 surface temperature isotherm (Fig. 4.) 



Ovchinnikov (1970) reported that commercial con- 

 centrations of white marlin occur near shores in areas 

 where less saline coastal waters mix with more saline 

 oceanic waters. De Sylva and Davis (1963) noted that 

 in the summer of 1959 the white marlin grounds off 

 southern New Jersey and Maryland were of higher 

 salinity than the surrounding inshore waters, and 

 were identifiable by an abrupt increase from lower to 

 higher salinity values. Those off Ocean City, Md., 

 were further characterized by low oxygen values sur- 

 rounded by high values. Important white marlin areas 

 showed distinctly high plankton volumes. 



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