A Study On the Growth and Age of the Jack Mackerel in the East China Sea∗

Abstract

In the present paper, growth and age of the jack mackerel, Trachurus japonicus (Temminck et Schlegel), are estimated, based upon the ring mark on scale stripped from the 610 fish caught by purse seine operated by a single boat in the East China Sea during the three years from 1957 to 1959. Results obtained are as follows: 1) Ring marks on scale of the fish are formed twice a year, one presumably in summer and the other in winter. 2) The so-called Lee's phenomenon is observed, and the cause of the phenomenon is presumed to be due to shrinking of old tissue of scale. 3) Growth in length of the fish is given in Table 6, in Fig. 6 as well as in von BertalaHFFY's equation (2); and growth in weight is given in Table 7, in Fig. 8 and in equation (4). © 1964, The Japanese Society of Fisheries Science. All rights reserved.