若狭湾西部海域におけるタチウオの年齢と成長

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The age and growth of ribbon fish Trichiurus lepturus from the western Wakasa Bay were estimated using otoliths of 2, 373 specimens collected from June, 1981 to December, 1982. The annuli on otoliths were formed from February to March. The fish were divided into two broods from 1-ring radius (r1), that is, narrow type of brood (r1<2.0 mm) and wide type of brood (r1≥2.0 mm). It was estimated that the narrow and wide types were born from June to September and from April to June, respectively. The two types were similar in size at the full age, though females reached larger sizes than males. According to back-calculation of anal length at 1-ring formation, the wide type grew faster and attained larger sizes than the narrow one. There was no difference in growth rate between sexes for each type. Between 1- and 2-ring formation, the growth of the narrow type overtook that of wide type. Growth compensation during 1- and 2-ring formation seemed to be explained by a difference in the time of the first maturation between the two types and decrease of growth rate of the fast growing group due to maturation. It is estimated that the narrow and wide type of broods were recruited from the adjacent waters of the western Wakasa Bay and the western part of the Japan Sea (far west off Hyogo), respectively.
日本水産學會の論文