Figure 5.— Seasonal changes in modes derived from average 

 year's length frequencies of longline-caught striped marlin. A. 

 North Pacific Current area; B. East China Sea (long. 120°- 

 130°E). (From Koto, 1963a.) 



in the catch only after September, as fish larger than 

 100 cm and shows rapid growth right through the 

 winter. The failure of the fishery to capture many fish 

 below 100 cm makes it impossible to say what the ab- 

 solute ages of the groups are. 



The annual growths of the n + l and n+2 age groups 

 differ between areas and years. Koto (1963b) showed 

 that in the North Pacific Current area the yearly 

 differences in the length composition were caused by 

 differences in the average length of the n+l age group. 

 In the North Equatorial Current area, however, these 

 differences were probably caused by differences in age 

 composition and the relative abundance of the n and 

 n+l age groups. 



Koto (1963b) has shown growth rate to be affected 

 by population density. The very close inverse 

 relationship between growth of the n+ 1 age group and 

 the total fish abundance, or especially the abundance 

 of the n and n+ 1 groups is shown in Figure 6. The cor- 

 relation coefficients between growth of the n+l age 

 group and total fish abundance were -0.958 (df = 6) 



for the North Equatorial Current area and -0.737 (df 

 = 8) for the North Pacific Current areas. 



Royce (1957) suggested the maximum size reached 

 by striped marlin is less than 226.8 kg (500 pounds). 

 Records were given as follows: 172.8 kg (381 pounds) 

 off New Zealand; 142.4 kg (314 pounds) from Pacific 

 equator; a "questionable" record of 196.9 kg (434 

 pounds) from the Hawaiian market, where normally 

 only occasional specimens approach 136.1 kg (300 

 pounds); a somewhat questionable record because of 

 possible confusion with the blue marlin of 219.1 kg 

 (483 pounds) from Chile; the world's record, taken off 

 California, was 692 pounds, which was based on a 

 misidentified blue marlin. 



The theoretical maximum length of about 290 cm 

 mentioned in section 3.31 is equivalent to 259.5 kg 

 (572 pounds). A fish of 290 cm was taken by longline 

 in the South Pacific (Honma and Kamimura, 1958). 



Average semimonthly condition factors (K) com- 

 puted 



K = 



W X 10 6 



where W is whole fish weight in kg 

 L is eye-fork length in cm 



for eastern Pacific fish ranged approximately from 

 0.80 to 1.26 (Eldridge and Wares, 1974). 

 In the East China Sea, condition factor 



K = 



W 



where W = gilled and gutted weight in kan (= 3.75 

 kg) 

 L = eye-fork length in m 



was found to increase with body length from about 8 

 at 110 cm to a peak of about 10 at 180 cm and then to 

 decline to about 9 with larger fish up to 230 cm 



53 '54 55 '56 



FISHING YEARS 



Figure 6.— Relation between total fish abundance and growth of 

 the n + 1 age group. A North Equatorial Current area; B. North 



Pacific Current area. growth per year; hook rate. 



(From Koto, 1963b.) 



146 



