number of sailfish caught by one longline. His es- 

 timates for the East China Sea and for the Okinawa 

 region were 2,462 and 624, respectively, which was less 

 than for striped marlin or black marlin but greater 

 than for blue marlin or swordfish. 



Ovchinnikov (1970) reported a high degree of 

 schooling in sailfish off West Africa from the frequen- 

 cy of occurrence on neighboring hooks along a tuna 

 longline. He found percentage catches on adjacent 

 hooks extremely high; often sailfish were caught, or 

 lost, from every hook for a length of several 

 kilometers. 



4 POPULATION 

 4.1 Structure 



4.11 Sex ratio 



Ueyanagi et al. (1970) examined 353 sailfish from 

 the Atlantic and found 208 females and 145 males, 

 and Nakamura (1971) also reported on predominance 

 of females in the Gulf of Mexico sport fishery. He ex- 

 amined 81 sailfish over a period of 4 yr and found an 

 overall ratio females to males of 2.4:1. 



Nakamura (1949) stated that the sex ratio of 

 sailfish in the East China Sea area was about even 

 and did not change greatly throughout the year. 

 Williams (1964) found a sex ratio males to females of 

 3.25:1 in 17 specimens captured by longline gear off 

 East Africa. He later (Williams, 1970) examined sport 

 catches off Malindi, Kenya, and found a sex ratio 

 males to females of 2:1. Merrett (1971) examined 79 

 sailfish caught by longlines off East Africa and found 

 males predominating, although not as greatly as in 

 Williams' sample. In the inshore troll fishery, Merrett 

 noticed no significant deviation from a 1:1 ratio. 



4.12 Age composition 



De Sylva (1957) concluded from his analysis of age 

 and growth of sailfish off southern Florida that most 

 of the population consisted of fish less than 3 yr old. 

 He stated that the winter sport fishery is almost en- 

 tirely dependent upon fish which are about 6 and 18 

 mo old. In the summer, the majority caught are 1- and 

 2-yr-old fish. 



Williams (1970) stated that if growth rates for the 

 Atlantic and Indian oceans were similar, then the 

 majority of the sailfish caught off Kenya are over 3 yr 

 old. He believed that the single mode in length fre- 

 quencies of sailfish caught off East Africa undoubted- 

 ly included at least two successive year classes. 

 Williams added that growth rates may not be similar, 

 however, and the larger sizes of Pacific and Indian 

 ocean sailfish may indicate much longer life or some 

 other factor. 



4.13 Size composition 

 De Sylva (1957) examined length frequencies of 



over 9,000 sailfish from off southern Florida (Fig. 6). 

 The majority of the sport catch range from about 102 

 to 140 cm trunk length (posterior edge of the orbit to 

 the anterior insertion of the caudal keels) or 173 to 229 

 cm total length (tip of upper jaw to vertical line drawn 

 between tips of caudal lobes) with a wide range in 

 weight from 6.0 to 49.4 kg. The second largest group is 

 from 61 to 94 cm trunk length averaging under 6 kg. 

 The small fish begin to appear in the catch in late 

 summer, becoming prominent in November, 

 December, and January. De Sylva stated that these 

 fish are the incoming year class. 



Ueyanagi et al. (1970) found a unimodal distribu- 

 tion in length frequencies of sailfish caught on 

 longlines in the Atlantic. The majority were from 125 

 to 165 cm body length (from posterior edge of orbit to 

 centralmost caudal rays). The largest sailfish caught 

 by sport fishing gear from the Atlantic is a 55.8-kg 

 specimen caught off the Bahamas in 1950. 



Williams (1970) found a unimodal distribution in 

 length frequencies of sailfish caught in the sport fish- 

 ery at Malindi, Kenya (Fig. 7). The majority ranged 

 from 203 to 254 cm fork length (tip of snout to cen- 

 tral rays of the caudal fin) or from 224 to 279 cm total 

 length (same as de Sylva's total length) with a weight 

 range of from 18.1 to 47.2 kg. Williams reported that 

 the Kenya record for 1957 weighed 62.1 kg. Merrett 

 (1971) examined 77 sailfish caught on longlines off 

 East Africa. He also found a unimodal distribution 

 with the majority of the specimens between 160 and 

 185 cm body length (center of orbit to tip of shortest 

 caudal ray). 



Koto et al. (1959) presented length frequencies of 

 sailfish caught by longlines in the East China Sea 

 (Fig. 8). Size ranged from 105 to 240 cm body length 

 (tip of lower jaw to central rays of caudal fin). Sixty 

 percent were from 165 to 190 cm body length. The dis- 

 tribution is essentially unimodal except in June when 

 a group of 125 to 150 cm fish suddenly appeared in the 

 catch. Koto et al. believed that these small fish enter 

 the East China Sea from other areas during this 

 month. The largest sailfish recorded on sport fishing 

 gear in the Pacific is a 100.2-kg specimen caught near 

 the Galapagos Islands in 1947. 



Length-weight relationships have been reported by 

 de Sylva (1957), Merrett (1968b, 1971), Kume and 

 Joseph (1969b), Williams (1970), Nakamura (1971), 

 and Jolley (1974). These results are summarized in 

 Table 8. None but Jolley were able to detect any 

 differences between sexes. Nakamura (1949) stated 

 that sex differences, if any, were inconspicuous in 

 Pacific sailfish. 



4.2 Abundance and Density (of Population) 

 4.21 Average abundance 

 Nothing found in the literature. 



112 



