Abstract

Sawara, Scomberomorus niphonius (CUVIER et VALENCIENNES), is a commercially and ecologically important species in the Inland Sea of Japan. The main fishing seasons are from March to June (spawning season) and from September to November (feeding migration season). Angling and gill-net are important types of fisheries. The present authors conducted trial fishing from 1963 to 1966 and collected specimens for studies. Juveniles (Plate 1) caught by commercial boat seine in the water off Tushi of Awaji Island in September 1966 were also used. The results are summarized as follows: 1) Correlation were calculated for some combinations of total length (T. L), fork length (F. L), head length (H. L), and otolith length (O. L). Regression formulae in terms of g and mm are, F. L=0.856 T. L+30.21 (Fig. 2) B. W=8.512×10-6×F. L2.990 (Fig. 3) O. L=0.0427×F. L0.887 (Fig. 7) H. L= 0.545×F. L0.836 (Fig. 8) O. L=0.0979H. L+0.32 (Fig. 9) 2) In order to locate the position of otolith, a linear relation between the length from snout to the front tip of auditory capsle (S-Ac) and the head length was applied, (S-Ac)=0.488H. L+1.30 (Fig. 6) 3) The otolith of this species is brittle and weak. The hind part of otolith shows translucent zones and opaque zones. It was assumed that the translucent zones are winter rings (Table 3, Fig. 5 and 10 and Plate 1). Growth of fish is estimated as shown in Table 4.

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