Natural survival rate and rate of growth were estimated for Pagrosomus major (TEMMINCK et SCHLEGEL) and Pseudosciaena undovittata JORDAN et SEALE, the former of which have shown a remarkable decline, while the latter have maintained almost constant level, in the catch by trawlers in the China Seas, during the last ten or more years. With the assumption of the constant annual recruits to the stock, the relations among the fishing rate, the size of stock and the total catch were formulated. Comparing the yearly variations between the catch by experimental trawling, averaged per haul, and the annual yield of the trawl fisheries, we can estimate the recent fishing rate in the fisheries to be •31 to •33. It can be concluded that if the fishing rate will unaltered. the parent fish will so diminish as to become unable to maintain the stock of Pagrosomus major, and that both the stock and the catch will decrease rapidly till about one fourth of their present amount.
