million eggs were contained in one ovary of a 154- 

 pound striped marlin landed in Honolulu. The other 

 ovary of this fish was immature. 



3.16 Spawning 



Examination of size-frequency distributions of egg 

 diameters (Eldridge and Wares, 1974) indicates only 

 one spawning per season. 



In the western Indian Ocean it appears that the 

 high catch rates during the northeast monsoon period 

 which peak from December to February are associated 

 with a postspawning feeding migration (Williams, 

 1967; Merrett, 1971). Spawning must occur elsewhere 

 in the Indian Ocean. 



From larval occurrence, spawning was suggested to 

 take place in the Banda and Timor seas during 

 January to February (Ueyanagi, 1959). On the basis of 

 larval occurrence, Jones and Kumaran (1964) stated 

 that striped marlin spawn in the western Indian 

 Ocean during December-January between lat. 10° 

 and 18°S and in the eastern Indian Ocean during Oc- 

 tober-November between lat. 6°N and 10°S. Further- 

 more mature females are known to occur in March- 

 May in the Bay of Bengal and in October-December 

 in the waters south of the Lesser Sunda Islands 

 (Ueyanagi, 1964). 



In the western Pacific, mature females are found 

 from lat. 15° to 30° (north and south) in early 

 summer, from May to June and October to January in 

 the northern and southern hemispheres, respectively. 

 Larvae are also found in these areas (Ueyanagi, 1964). 

 Nakamura (1949) stated that in the Formosa area, 

 spawning is thought to take place mainly in the South 

 China Sea with its peak occurring from April to May. 

 Koga (1967) reported that the spawning areas (lat. 

 18°-30°S) in the western South Pacific is also the 

 main fishing area and that the period of spawning cor- 

 responds to the season of northward migration which 

 occurs from September to November. 



In the eastern Pacific, the spawning season also 

 appears to be the early summer in each hemisphere, 

 quarters II and III in the northern and quarters IV and 

 I in the southern. Highest frequencies of spawning fish 

 occur from May to June in the north and November to 

 December in the south (Kume and Joseph, 1969b). 

 Evidence of spawning in the eastern Pacific is based 

 only on relative gonad sizes of females. The northern 

 spawning area appears to be isolated in a narrow band 

 from long. 107° to 114°W extending from about lat. 6° 

 to 19°N (Kume and Joseph, 1969b). 



Ovaries of striped marlin caught in the Mexican 

 sport fishery undergo rapid development in June; ripe 

 fish were never observed (Eldridge and Wares, 1974). 

 Japanese fishermen, however, have reported ripe and 

 running ripe striped marlin in the waters around 

 Socorro Island from June to October (J. L. Squire, Jr., 

 Southwest Fisheries Center, National Marine 

 Fisheries Service, NOAA, La Jolla, Calif., pers. com- 

 mun.). 



The southern spawning area appears fairly well con- 

 fined to lat. 20°-25°S and long. 125°-130°W (Kume 

 and Joseph, 1969b). Highest frequencies of the mature 

 females occur in November and December. 



Nakamura (1949) stated that sex ratios approached 

 1:1 at the peak of the spawning season. However, it 

 was found that males dominate during the spawning 

 season in the northwestern Pacific (Nakamura, 

 Yabuta, and Ueyanagi, 1953). Kuma and Joseph 

 (1969b) also found a high proportion of males in the 

 spawning groups in the eastern Pacific. Male:female 

 ratios ranged from 1.8 to 6.6 in spawning groups, 

 whereas in nonspawning groups they tended to be less 

 than 0.5 and to decrease with increased size of fish. 



3.17 Spawn 



There is little information pertaining to the eggs of 

 this species. Nakamura (1949) mentioned that the ex- 

 ternal morphology of the eggs of striped marlin closely 

 resembles that of sailfish eggs which are spherical, 

 transparent, and buoyant, with a single oil globule 

 and with no special structure on the egg membrane. 

 Morrow (1964) reported that the ovarian eggs of 

 striped marlin from New Zealand average about 0.85 

 mm in diameter. Size of the ovulated eggs of this 

 species is presumed to exceed 1 mm in diameter con- 

 sidering that the mean diameter of eggs for shortbill 

 spearfish is 1.442 mm and for sailfish is 1.304 mm as 

 reported by Merrett (1970). 



3.2 Pre-Adult Phase 



3.21 Embryonic phase 

 No information available. 



3.22 Larval phase 



The postlarval stage of striped marlin is described 

 in detail by Ueyanagi (1959). The study was based on 

 40 specimens ranging from 2.9 to 21.2 mm in standard 

 length, collected from the northwestern Pacific, South 

 Pacific, and the Indian Ocean. These specimens were 

 captured by surface tows of the larvae net. The 

 morphology of the striped marlin postlarvae is similar 

 to that of other istiophorid species in the development 

 and degeneration of head spination, fin formation, 

 pigmentation, etc. Figure 3 from Ueyanagi (1959, 

 1963a) represents the postlarval stage of this species 

 from an early stage with short snout to an advanced 

 stage with elongated jaws. The snout begins to 

 lengthen at around 7 mm standard length. Head 

 spination becomes most conspicuous at this size. Fin 

 rays of each fin reach their full complement at around 

 20 mm standard length. Pigmentation extends almost 

 all over the body surface and on the dorsal fin mem- 

 brane at this size. The dorsal fin begins to increase its 

 height at around 10 mm and stands very high like a 

 sail in larvae exceeding 20 mm. The key diagnostic 

 character for the striped marlin larvae was reported as 



141 



