東北海區に於ける流網による漁獲サンマの組成(豫報II)

抄録

On the same samples as previously reported and by the L_EA'S back-calculation method, the body length, l₁, l₂ or l₃, at the time, at which the first, second or third year ring was performed, was calculated separately with the III age group, with IV age group which has the spawning mark on the scale and with IV age group which does not (Fig. 1, Table 1). Following results were obtained: -
(1) The proportion of the IV with the spawning mark is 77-88% in the waters north of Tiba Pref, and 65% in the water off Mie Pref.
(2) Of each one of the three categories, every calculated length, l₁, l₂ or l₃, does not show any local difference.
(3) The calculated lengths l₁, l₂ and l₃, of the IV with the spawning mark are larger than those of the IV without the spawning mark.