A PRELIMINARY STUDY ON THE MORPHOLOGY, GROWTH AND FEEDING HABITS OF YOUNG PSEPHURUS GLADIUS IN THE ESTUARINE REGION OF THE CHANGJIANG (YANGTZE) RIVER

Forty nine young Psephurus gladius with body length ranging 80—530mm.collected from the estuary of the Changjiang (Yangtze) River during June to October in 1985 were investigated. The main results in relation to the morphology, growth and feeding habits are as follows. (1) All specimens of the young are similar with the adult in morphology, but the correlations between body length and BL./eye-diameter, and BL./rostral barbel length are significiant positively; (2) The equation of growth in length from 21 June to 12 October is given as Lt=79.9723e0.0213t, where Lt stands for BL. (in mm.) and t for number of days. The rate of relative growth was found to be highest during August. The relationship between body-length (in mm.) and body-weight (in g.) may be expressed by W=1.5654-6 BL.3.1432; (3) Food of different quantity were observed in stomach of all specimens and the average fullness index of stomach reaches 198.46. It is a predatory fish feeding mainly on benthic small shrimps, fishes etc., involving 16 identified species belonging to eight groubs. (4) Concerning the depressed population of this precious and rare fish, the authors propose that suitable protective measures in the estuarine region of the Changjiang River should be taken.