A PRELIMINARY STUDY OF THE FISHERIES BIOLOGY OF MAIN COMMERCIAL FISHES IN THE MIDDLE AND UPPER REACHES OF THE YANGTZE RIVER

According to the monitoring data of fishery resources in the middle and upper reaches of the Yangtze River in 1996-1999, this paper deals with the fishery biological characteristics of ten species of major commercial fishes. The population growth parameters(K, L∞, W∞),total mortality coefficient, natural mortality coefficient, fishing mortality coefficient, total surviving rate, total mortality rate, natural mortality rate, fishing mortality rate and exploitation rate were estimated by the model of von Bertalanffy, Key and Beverton Holt etc. The exploitation status of the stocks was also discussed. In view of the existing problems, the authors make some suggestions on the fishery management.