SKILLMAN and YONG: GROWTH CURVES FOR TWO MARLINS 



phase migrating poleward, but at lower latitudes, 

 at the same time as the primary stock. Possibly 

 these fish associate with blue marlin of about the 

 same size that migrate into Hawaiian waters in 

 the third quarter. 



Estimates of von Bertalanffy growth pa- 

 rameters for both sexes were first obtained using 

 for females and using 12 and 11 (deleting oldest) 

 age-groups for males (Table 4, smooth curves in 

 Figure 3). The standard errors of estimates were 

 slightly smaller than those for the individual 

 cohorts but still not what could be considered 

 small. When the oldest age-group for males was 

 deleted from the calculations, L^ for females was 

 11 to 12 cm greater than for males. Using all of the 

 age-groups for males, the estimate of L^ increased 

 substantially. 



Although this paper deals with growth, the 

 length composition and age of striped marlin as 

 found in this study have some relevancy to the 

 problem of migration. First, Matsumoto and 

 Kazama (1974) hypothesized that striped marlin 

 migrate out of Hawaiian waters to spawn, most 

 likely to the western North Pacific. The calculated 

 mean length of the last female age-group found in 

 the Hawaiian fishery (age 4.2 yr) corresponded to 

 the length at first maturity found by Eldridge and 

 Wares (1974) and Kume and Joseph (1969) for the 

 eastern tropical North Pacific. Thus, our data 

 established that as striped marlin reached the 

 length corresponding to sexual maturity, they 

 became unavailable to the local fishery. Second, 

 Kume and Joseph (1969) indicated that there was a 

 tendency for average length to increase in the 

 southern areas of the Japanese longline fishery in 

 the eastern tropical North Pacific, and it seemed to 

 us from their charts that there was also a western 

 component to the increasing average lengths. 

 Eldridge and Wares (1974) believed that maturing 

 striped marlin moved out of the range of the sport 

 fisheries based in southern California and Mexico; 

 and Squire (1974) suggested that the movement of 

 striped marlin away from the Baja California area 

 might be to the area of the Revilla Gigedo Islands 

 where fish with ripe gonads have been collected 

 and where behavior suggestive of spawning ac- 

 tivity has been observed by the Japanese. While 

 the range of our length data was similar to that 

 found in the eastern tropical Pacific, the last 

 age-group recognizable in our data comprised less 

 than 10% of the total frequency whereas similar- 

 sized fish seemed to be well represented in the 



southern and western areas of the eastern tropical 

 North Pacific longline fishery. Thus, it seems 

 apparent that the fish leaving the fishery off the 

 American coast do not migrate through the 

 Hawaiian fishery in any appreciable numbers. 

 However, the capture of a striped marlin, tagged 

 off Baja California, 322 km southwest of the 

 Hawaiian Islands indicates that some eastern 

 Pacific fish move into the vicinity of the Hawaiian 

 Islands. Finally, our analyses do not provide any 

 information on the direction of emigration from 

 the Hawaiian fishery. 



GROWTH OF BLUE MARLIN 



Results— Analysis of Pooled Data 



The number of age-groups, as separated by the 

 computer program ENORMSEP, varied from 

 three in the third quarter for males to as many as 

 eight in the first quarter for females (Table 5). The 



Table 5.-Statistics for blue marlin age-groups by quarter and 

 sex for analysis of pooled data. Estimates of mean fork length, 

 FL\ percent representation of the age-group, %; the numerical 

 sample size for the group, ti; the total sample size, A^; and the 

 chi-square goodness of fit value, x". were obtained from the 

 computer program ENORMSEP. 



563 



