GROWTH OF PACIFIC SAURY, COLOLABIS SAIRA, IN 

 THE NORTHEASTERN AND NORTHWESTERN PACIFIC OCEAN' 



YosHiRO Waia.nabe,2 John L. Builer,^ and Tsukasa Mori^ 



ABSTRACT 



Growth of the Pacific saury, Cololabis saira, from the northeastern and northwestern Pacific Ocean was 

 studied using otolith growth increments. We found that growth of Pacific sauries from the western Pacific 

 was higher than that from the eastern Pacific. Assuming that otolith growth increments are deposited 

 daily, average growth rates from hatching up to 1 year old were 0.62 mm/d in the eastern and 0.85 mm/d 

 in the western Pacific. Because the growth rate changes at around 100 mm, two curves were used to 

 model the growth of Pacific saury in the western Pacific: one for fish up to 100 mm and the other for 

 fish larger than 100 mm. Based on counts of daily increments. Pacific sauries may be short lived. The 

 oldest specimen examined was only 14 months old. 



The Pacific saury, Cololabis saira (Brevoort), is 

 distributed throughout the North Pacific Ocean and 

 is one of the most important commercial fishes in 

 the northwestern Pacific. The average annual catch 

 of Pacific saury in Japan has been approximately 

 200,000 1 (metric tons) in the last 20 years (Statistics 

 and Information Department, Japan 1985). The 

 catch has varied by an order of magnitude in the 

 last 20 years from a minimum of 63,000 t in 1969 

 to a maximum of 406,000 t in 1973. Fluctuation in 

 stock size is a major factor in catch variability 

 although economic factors such as fish price may 

 also affect total landings. However, the causes of 

 stock fluctuation in the western Pacific remain 

 unknown. In the eastern Pacific, the Pacific saury 

 has not been exploited but is recognized as a poten- 

 tial fishery resource (Ahlstrom 1968; Smith et al. 

 1970). 



Investigations of the Pacific saury have mainly 

 been devoted to such subjects as systematics, abun- 

 dance, distribution, migration, and formation of 

 fishing ground in relation to oceanographic condi- 

 tions (e.g., Hubbs and Wisner 1980; Smith et al. 

 1970; Odate 1977; Fukushima 1979; Sablin and 

 Pavlychev 1982; Gong 1984). Age determination and 

 growth, however, remain controversial (Hatanaka 

 1955; Hotta 1960; Novikov 1960; Sunada 1974; Kim 



"Contribution No. 429 from Tohoku Regional Fisheries Research 

 Laboratory. 



^Tohoku Regional Fisheries Research Laboratory, Fisheries 

 Agency, Shiogama, Miyagi 985, Japan. 



^Southwest Fisheries Center La Jolla Laboratory, National 

 Marine Fisheries Service, NOAA, P.O. Box 271, La Jolla, CA 

 92038. 



*Facu]ty of Fisheries, Hokkaido University, Hakodate, Hokkaido 

 041, Japan. 



and Park 1981), notwithstanding their critical im- 

 portance for fish stock assessment. 



The discovery of daily increments in the otoliths 

 of fishes (Pannella 1971) has made it possible to 

 estimate age and growth of larval and juvenile fishes 

 accurately. Daily increments have been used to age 

 many species of fishes (Jones 1986). Nishimura et al. 

 (1985) reported the presence of growth increments 

 in Pacific saury otoliths observed by scanning elec- 

 tron microscopy and suggested that it is possible to 

 estimate age and growth of Pacific saury by using 

 daily increments in the otolith. The purpose of this 

 paper is to determine the age of Pacific sauries from 

 the eastern and western North Pacific using daily 

 increments and to compare the growth rates in these 

 areas. 



MATERIALS AND METHODS 



We read otoliths of 75 Pacific sauries from the 

 northeastern and 172 from the northwestern Pacific 

 Ocean. Details of sampling and methods of reading 

 otoliths are summarized in Table 1 and Figure 1. 

 Additional samples from the western Pacific were 

 used to determine the relation between otolith size 

 and fish length. Fish from the eastern Pacific were 

 fixed and preserved in 80% alcohol after capture, 

 and those from the western Pacific were stored 

 frozen and thawed when processed. Because speci- 

 mens frequently have damaged upper jaws, knob 

 length (the distance from the tip of the lower jaw 

 to the posterior end of the muscular knob at the base 

 of a caudal peduncle) is the standard measure of 

 body size in Pacific saury. All body lengths in this 

 paper are knob length. 



Manuscript accepted March 1988. 



FISHERY BULLETIN: VOL. 86, NO. 3, 1988. 



489 



