WATANABE ET AL.: GROWTH OF SAURY 



KnL = 5.90 exp((0.0865/0.0293Xl - e(-oo293(/-5)))) 

 and for fish larger than 100 mm KnL was 



KnL = 3.01 exp((0.0592/0.0126)(l - e(-o.oi26(/-5)))) 



The estimated mean square error, 215.7, of the two 

 curves was smaller than that for a single curve, 

 351.7. The two-curve model fits much better for the 

 smaller size range up to 100 mm. The estimated 

 mean square error of the two-curve model for this 

 size range, 75.7, was much smaller than that of the 

 one-curve model, 240.8. 



The growth rate of Pacific saury in the eastern 

 Pacific was slower than that in the western Pacific 

 (Figs. 3, 4). The knob length of saury in the eastern 

 Pacific would be about 75 mm at 100 rings, 170 mm 

 at 200 rings, and 220 mm at 300 rings, whereas in 

 the western Pacific knob length would be about 100 

 mm at 100 rings, 230 mm at 200 rings, and 300 mm 

 at 300 rings. Assuming that the rings are formed 

 daily, overall growth rates of the first one year 

 of their life were 0.62 mm/d and 0.85 mm/d for 



the eastern and western Pacific Ocean, respectively. 



The largest specimen examined was 330 mm from 

 the western Pacific, which had 328 increments, and 

 the oldest fish, also from the western Pacific, which 

 measured 320 mm, had only 418 increments. These 

 fish would be classified as very large or large by 

 Novikov's categories offish size composition (Novi- 

 kov 1960, 1973). The largest fish examined from the 

 eastern Pacific was 235 mm and had 241 incre- 

 ments. Hughes (1974), however, reported larger fish 

 from the eastern Pacific. 



In Pacific saury from the western Pacific, the rela- 

 tion between otolith radius in f^m (OR) and knob 

 length in mm (KnL) was linear on logarithm- 

 logarithm coordinates (Fig. 5). The equation com- 

 puted by the geometric mean regression (Ricker 

 1973) was 



In (OR) = 2.33 + 0.749 In (KnL) (r = 0.979). 



The otolith radius at hatching (5.9 mm KnL) cal- 

 culated by this formula was 38.9 ^im, which was 12 

 /im larger than the radius of the presumed hatch- 

 ing ring. 



200 - 



E 

 E 



I 



H 



o 



z 



UJ 



_J 



CO 



o 



100 - 



00427 f ^(-0.0115(l-5))\ 

 0.0115 ^ ^® ' 



KnL: KNOB LENGTH 



I: NUMBER OF INCREMENTS 



100 200 



NUMBER OF INCREMENTS 



Figure 3.— Growth curve of the eastern Pacific saury. 



300 



493 



