male then catches the eggs in the basket-like opening 

 of his gill covers and lets them pass out through his 

 mouth." LaMonte and Marcy (1941) question the 

 feasibility and utility of the latter operation, but the 

 observation of paired spawning may nonetheless be 

 basically accurate. 



3.17 Spawn 



White marlin eggs have yet to be accurately iden- 

 tified according to Morrow (1965), but are free- 

 floating in the water column. De Sylva and Davis 

 (1963) assume that ripe eggs would appear translu- 

 cent. 



3.2 Preadult Phase 



3.21 Embryonic phase 



Embryonic development of the white marlin has 

 not been observed and information concerning this 

 phase of life is not available. 



3.22 Larvae phase 



Other than observations made on planktonic 

 samples of larval white marlin, little is known about 

 their development and activities during this stage of 

 life. The larval white marlin has heavy, pointed oper- 

 cular spines and lacks the characteristic long bill of 

 the adult (Scotton and de Sylva, 1972) (Fig. 8). 



The postlarvae of white marlin are also rare. De 

 Sylva (1963) gives a detailed description of a 125-mm 

 specimen collected off Wilmington, N.C. This fish is 

 notable in that it bears a saillike dorsal fin with four 

 distinct ocelli near the base. A second very similar 

 specimen (191 mm in total length) was taken off the 

 northwest coast of Cuba (Anon., 1968). 



Information on the behavior and continuous 

 development during this period in the life cycle, 

 however, is not available. 



3.23 Adolescent phase 



No material in the range between these postlarvae 

 and the 904-mm and 964-mm specimens mentioned in 



- 



Figure 8. — Baby white marlin, about '/g inch (3.2 mm) long, 

 with heavy, pointed spines and lacking the characteristic bill. 

 (Drawing by Joy Godfrey Alexander, from Scotton and de 

 Sylva, 1972, Figure p. 200.) 



1.31 are available. As noted above, the latter 

 specimens have attained all the adult characteristics 

 except that the middle of the first dorsal fin is 

 somewhat higher, the pectorals very slightly shorter, 

 and the pelvics longer than in adults. Maturity occurs 

 at a length (from eye to fork of tail) of about 130 cm 

 (145-cm body length) (Ueyanagi et al., 1970). This is 

 equivalent to a weight of about 37 pounds (17 kg) for 

 females and 31 pounds (14 kg) for males (de Sylva and 

 Davis, 1963). These authors and Nakamura and Rivas 

 (1972) indicate that very few smaller (immature) 

 white marlin are taken in the U.S. sport fisheries. 

 Ueyanagi et al. (1970), however, show that many 

 white marlin in this immature size range are taken by 

 the Japanese longline fishery in equatorial waters lat. 

 10°S to 10°N, and north of lat. 10°N in May-October. 

 Most of the small fish taken from lat. 10° S to 30° N 

 are males. Most of the available biometric data, 

 however, are from mature fish. 



3.3 Adult Phase 

 3.31 Longevity 



Weight frequency distributions and tag returns 

 suggest that the white marlin may be longer lived 

 than was once believed. Each of two weight frequency 

 polygons for fish taken off Maryland and southern 

 New Jersey (de Sylva and Davis, 1963, Figs. 4, 5) show 

 several peaks. If these peaks actually represent year 

 classes, as they seem to, this is a good indication of 

 longevity. In addition several tagged white marlin 

 have been recaptured after over 4 yr at large (Mather 

 et al., 1974) including two recent recaptures of fish 

 which had been out over 71 mo (unpublished WHOI 

 data). Since these fish were not remarkably small 

 when tagged, the life span must sometimes exceed 6 



yr- 



3.32 Hardiness 



White marlin seem to be of a reasonably hardy 

 nature. Mortality rates for fish which had been sub- 

 jected to the rigors of capture on hook and line and 

 tagging and had been at large for from less than 1 mo 

 to more than 48 were 30% per year with 95% con- 

 fidence limits of 23% and 36% and a coefficient of in- 

 stantaneous total mortality of 0.36 ± 0.10 (Mather et 

 al., 1974). 



These fish do seem, however, to be somewhat 

 temperature sensitive. Earle (1940) reported that in 

 the Ocean City, Md. fishery, white marlin vanished 

 after a sudden drop in water temperature of a few 

 degrees and returned when water temperature return- 

 ed to normal. 



There is no information on survival of white marlin 

 in confined environments, or on variations in har- 

 diness with age, size, or physiological states. 



71 



