Growth Curves of Blue-fin Tuna and Yello-fin Tuan based on the Catches near Sigedera, on the West Cosast of Prov. Izu

Abstract

No investigation has been made on the scale and otolith of the tuna from the Seas of Japan with reference to the growth rate of the fish. In the present paper are given frequency histograms (Figs. 2 and 5) showing body-weight distribution of bluefin tuna (Thunnus orientalis Temminck & Schlegel) and yellowfin tuna (Neothunnus macropterns Temminck & Schlegel) from Sigedera fishing ground which is situated at north-eastern corner of the Suruga Bay (Fig. 1). The data were obtained from 1924 to 1931 inclusive, and can be divided into several age-groups as plotted in Figs. 4 and 6, in which solid circle indicates individual fluctuation of the body-weight and encircled dot shows the average body-weight of a large number of specimens which were caught there at the same time and nearly of the same weight. The curves are free-hand smoothing.