WATANABE ET AL.: GROWTH OF SAURY 

 1000 I- 



500 



CO 



Q 

 < 

 CC 



o 



I- 



o 



100 



40 



In OR =2.33 +0.749 In KnL 

 r = 0.979 



OR: OTOLITH RADIUS 

 KnL: KNOB LENGTH 



J \ \ \ 



10 



50 100 



KNOB LENGTH (mm) 



200 300 



Figure 5.— Knob length and otolith radius relationship of the western Pacific saury. 



Previous studies on age and growth of the Pacific 

 saury have based on annuli on scales and/or otoliths. 

 Sunada (1974) found five age groups in Pacific 

 sauries off southern Oregon, California, and Baja 

 California. Mean fork lengths of age groups were 

 171, 220, 246, 270, and 268 mm for age 0, 1, 2, 3, 

 and 4, respectively. Hughes (1974) examined age 

 composition of 5,248 sauries collected in waters off 

 California up to Vancouver Island. He found spring- 

 and autumn-bom fish in his samples, but little differ- 

 ence was noted in growth rates between two groups. 

 Approximate knob lengths of 1.0- to 5.0-year-old fish 

 were 180, 230, 255, 290, 310 mm. The growth rates 

 given in these two papers are not very much dif- 

 ferent. The saury grows at 0.5-0.6 mm/d up to 1 

 year old, which is almost equal to our growth rate 

 in the eastern Pacific, 0.62 mm/d. Hatanaka (1955) 

 found five age groups in the western population of 

 the saury, 0-4 years old, and estimated mean body 

 length of age groups to be 80, 160, 230, 265 mm for 

 1- to 4-year-old fish, respectively. Novikov (1960, 

 1973) divided sauries captured in autumn into five 

 size groups, very small ( - 200 mm), small (201-240), 

 medium (241-290), large (291-320), and very large 

 (321-(-), and assigned the small, medium, and large 



to 1-, 2-, and 3-year-old with maximum 5-year-old 

 fish. 



A different model of Pacific saury growth in the 

 western Pacific was proposed by Hotta (1960) based 

 upon a hypothesis of two subpopulations. He separ- 

 ated the saury into spring-spawning and autumn- 

 spawning populations based upon the observations 

 of fish size composition, scales, otoliths, and num- 

 bers of vertebrae. He assigned four ages of half year 

 intervals, 1.0, 1.5, 2.0, 2.5 years old, to fish 210-240, 

 260-280, 290-300, and 310-330 mm, respectively. 

 The growth rate up to 1 year was 0.6-0.7 mm/d. Kim 

 and Park (1981) examined Pacific sauries from 

 Korean waters and found four size groups of four 

 different ages of half-year intervals as well. They 

 presented two growth models for each of two sub- 

 populations, spring and autumn spawning, based 

 upon the von Bertalanffy equation. The sizes at ages 

 were almost identical to those of Hotta (1960). How- 

 ever, the hypothesis of two saury subpopulations in 

 the western Pacific is not supported by electro- 

 phoretic analyses of genetic separation (Numachi 

 1971; Hara et al. 1982). 



The average growth rate of the western Pacific 

 saury in this paper was 1.1 mm/d from to 8 or 



495 



