the testes and ovaries. Of 12 females studied by me 

 the range was 7.6 to 13.2% in five specimens; their 

 ovaries were in a resting condition. In the other seven 

 fish, the range was 16.7 to 20.8% and their ovaries 

 were developing but not yet ripe. In five males 

 studied, the range was 22.0 to 32.4% and their testes 

 were all ripe with much milt running in the ducts. No 

 males in the resting or developing stage were available 

 for comparison. 

 There is no information available on fecundity. 



3.16 Spawning 



Mather et al. (1972) believe that the two widely 

 separated concentrations of blue marlin in the 

 western Atlantic represent separate spawning pop- 

 ulations. They indicate that the evidence suggests 

 that the blue marlin in the North Atlantic spawn 

 mainly from July through September and those in the 

 South Atlantic spawn in February and March. These 

 authors further state that it is unlikely that a single 

 population of blue marlin spawns at two widely 

 separate locations at different times of the year. 



According to Erdman (1968) the occurrence of ripe 

 testes from May to November indicates a protracted 

 spawning season for the blue marlin off Puerto Rico. 

 He found females with well-formed eggs from late 

 May to September and a female with flowing ripe eggs 

 in September. Erdman assumes that July and August 

 are the peak spawning months because during that 

 period the sex ratio is nearly equal. 



De Sylva (1963) suggested May and June as the 

 spawning season for the blue marlin found in waters 

 off Florida and Bahamas. He also stated that mature 

 fish taken off Cape Hatteras in June appear to have 

 been recent spawners and that females taken in 

 September and October from Jamaican and Puerto 

 Rican waters have long since spawned. 



For the Pacific Ocean, information on spawning of 

 the blue marlin was summarized by Howard and 

 Ueyanagi (1965) and Strasburg (1970). From the oc- 

 currence of larvae, gonad condition, and sex ratio, 

 spawning is assumed to take place between about lat. 

 20°N and 10°S throughout the year. During the 

 summer season, however, spawning is assumed to 

 take place in the broader latitudinal area bounded by 

 lat. 30°N and 30°S. Males with freely flowing milt 

 have been captured in the central Pacific from 

 February to October, and May to July has been 

 regarded as the spawning season in the Philippine 

 area. 



Kume and Joseph (1969b) indicated that in the 

 southwestern portions of the eastern Pacific Ocean, 

 blue marlin spawn primarily during the southern 

 summer. 



Among the blue marlin specimens examined by 

 Royce (1957) from the central Pacific no ripe females 

 were found, but a number of males had freely flowing 

 milt in the gonads from February through October. 



Off Puerto Rico, the annual average male:female 

 sex ratio was 4:1 based on 328 specimens examined by 

 Erdman (1968). As already indicated, the 47 

 specimens examined by him in July and August show 

 a more nearly equal ratio of 25:22. Every September, 

 there is a sudden increase in the catch of males and 

 the ratio changes to 4.5:1. 



Of 39 specimens examined by de Sylva (1963) in 

 Jamaica during early October, 37 were males for a 

 ratio of 18.5:1. 



Nakamura and Rivas (1972) recorded sex ratios for 

 the northern Gulf of Mexico during the sport fishing 

 season (June through October) as follows. Off the 

 mouth of the Mississippi River (South Pass) the 

 male:female sex ratio was 1:5.6 in 1967, 1:7.7 in 1968, 

 1:4.8 in 1969, 1:8.0 in 1970, and 1:33 in 1971. Off 

 northwest Florida the male:female sex ratio was 1:2.5 

 (Destin) and 1:2 (Panama City). 



In the central Pacific, according to data presented 

 by Royce (1957), the mean annual male:female sex 

 ratio is 1.2:1. 



3.17 Spawn 



Subripe ova are opaque, white to yellow, and 0.3 to 

 0.5 mm in diameter. Transparent, spherical eggs flow- 

 ing out of a ripe ovary measure 1 mm in diameter 

 (Erdman, 1968). 



3.2 Preadult Phase 



3.21 Embryonic phase 



There is no information on the embryonic phase. 



3.22 Larval phase 



Various workers have contributed to the still very 

 incomplete knowledge of the larval and juvenile 

 stages of the blue marlin. Their findings are sum- 

 marized below. 



Gehringer (1956) described three unidentified lar- 

 vae 11.3, 21.0, and 45 mm long from the Atlantic. 

 These were later identified as blue marlin larvae by 

 Ueyanagi and Yabe (1959). These authors also 

 described eight specimens, 2.8 to 23.2 mm in length, 

 selected from about 400 larval blue marlin collected in 

 the western Pacific. Caldwell (1962) described two 

 postlarval blue marlin measuring 201.4 and 206 mm 

 in length from Jamaica. Ueyanagi (1964) reported 

 that as of that date 1,015 larval blue marlin, 3 to 33 

 mm (mostly under 7 mm), had been collected in the 

 Pacific by the Nankai Regional Fisheries Research 

 Laboratory. Eschmeyer and Bullis (1968) described 

 three larval (33.5, 35.3, and 51.5 mm) and one postlar- 

 val (194.1 mm) blue marlin from the western Atlantic. 

 Bartlett and Haedrich (1968) reported on 85 larval 

 blue marlin, 4.9 to 32.0 mm long from the 

 southwestern Atlantic. 



In summary, larval stages are fairly well known 



