On the white Pomfretof the East China Sea II : Relation between the Oceangraphical Condition and Distribution of the White Pomfret in the South-West Region of the East China Sea

Based on the data of the trawl fishing experiments and the oceanographic observations successively carried out in every march of the years 1969, 1973 and 1974 in the south-west region of the East China Sea, the relation between the hydrographic conditions and the catch of white pomfret (Pampus argenteus Euphrasen) were studied. As the result of study, the following several points were made clear. 1) The sea bottom topography of the studied area surrounding the point 28°N. Lat. and 127°E. Long. being rather flat and gradually deepening eastwards is suitable for trawl fishing ground. 2) The bottom water conditions during the time of observation in the above mentioned three years were as follows: the bottom water temperature ranges from 14.0 to 17.7°C, salinity from 33.15 to 34.71‰ and dissolved oxygen from 4.19 to 8.13 ml/L, respectively. The area of good catch is often recognized to develop at the front of water mass where the abrupt changes in temperature and some bendings of isotherm and isohaline exist. 3) At the time of good catch (weight of catch above 10.0 kg per hour) the range of sea bottom temperature was between 14.0 and 18.0°C, and the best catch was at the temperature of 17°C. 4) The sizes of white pomfrets (Pampus argenteus Euphrasen) collected in 1969 and 1973 are represented by the body lengths (Fork length) between 19 and 24 cm and those in 1974 are between 22 and 28 cm, respectively