Jaen (1964), however, stated that the majority of the 

 white marlin taken off Venezuela, mainly in August- 

 October, were males. 



4.12 Age composition 



No age determinations were found in the literature. 



4.13 Size composition 



The length composition of the white marlin popula- 

 tion as a whole is best illustrated by Figure 11, which 

 shows the length frequencies for samples of longline 

 catches in various seasons and oceanic areas. 



De Sylva and Davis (1963, Figs. 1-5) present weight 

 frequencies for white marlin caught in the sport 

 fisheries off Ocean City in 1940, 1941, and 1945-59; 

 off Atlantic City in 1958 and 1959; between Ocean 

 City and Atlantic City in 1959 and 1960; off Puerto 

 Rico in 1950-57; and off the Bahamas in 1956. They 

 state that if these marlin belong to the same popula- 

 tion, it seems that marlin may school together accord- 

 ing to size or sex at various seasons. 



The maximum documented size which we have 

 found for white marlin was 161 pounds (73.2 kg) and 8 

 feet 8 inches (264 cm) — the present world record rod 

 and reel catch from off Miami Beach, Fla., in 1938 

 (Anon., 1972a). 



We found no information on the density of size 

 groups, beyond the size composition data and catch 

 rates shown above. 



De Sylva and Davis (1963) showed that, at small 

 sizes [less than 68 inches (173 cm) fork length] female 

 white marlin tended to be heavier than males of the 

 same length (Fig. 12), according to the length-weight 

 formula (see 3.43): 



Males: W = 6.0 X 10-<L 3 - 6 

 Females: W = 4.6 X lO" 3 !, 3 - 



The constants were derived from measurements of 

 postspawning fish taken from June through 

 September between Atlantic City and Ocean City. 



Figure 12. — Length-weight relationship of white marlin, 

 Tetrapturus albidus, caught between Atlantic City, N.J. and 

 Ocean City, Md., July-September 1959 and 1960. Males are 

 represented by dotted line and closed circles; females are 

 represented by solid line and open circles. (From de Sylva and 

 Davis, 1963, Fig. 6 and caption.) 



4.2 Abundance and Density (of Population) 



4.21 Average abundance 



Since no estimates of population size are available, 

 the actual average abundance is unknown. 



4.22 Changes in abundance 



Local changes in abundance caused by 

 hydrographic conditions were discussed in 2.3. 



The apparent relative abundance of white marlin, 

 as indicated by catch rates of the Japanese longline 

 fishery in 1958-66 (Ueyanagi et al., 1970, Fig. 26), 

 declined slightly after reaching a peak in 1962. More 

 recent information (Table 6), however, shows that 

 this net downward trend has continued through 1970, 

 resulting in a decline from a maximum of 2.06 fish per 

 1,000 hooks in 1962 to 0.80 fish per 1,000 hooks in 

 1970. Important declines have occurred in the areas 

 (Fig. 13) in which the largest catches were taken: from 

 4.34 in 1962 to 1.86 in 1970 in BAH; from 10.77 in 1967 

 to 1.20 in 1970 in RIO; from 2.31 in 1966 to 1.00 in 1970 

 in NOW; and from 2.44 in 1966 to 0.62 in 1970 in GUI. 

 S. Ueyanagi (pers. commun.) has stated that the 

 average size of the white marlin taken in the fishery 

 has also declined with the catch rates. This is an ad- 

 ditional indication that the fisheries have actually 

 caused a decline in the abundance of the white marlin 

 stocks. 



120 



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FORK LENGTH, INCHES 



79 



