GROWTH CHARACTERISTICS OF COREIUS HETERODON IN THE MIDDLE AND UPPER REACHES OF THE YANGTZE RIVER

Coreius heterodon is a very important commercial species in the middle and upper reaches of the Yangtze River.No special report on the research in the growth characteristics of the fish is available so far.In this paper, one thousand and thirty specimens, which were collected from the middle and upper reaches of the Yangtze River during the years of 1990-1995, were investigated on the fish's growth biology.By means of biostatistics analysis, the relationship between body length, W(g), and body weight, L(cm), may be expressed as W = 0.005413L3.113(r = 0.9982).The von Bertalanffy equations for the species are as follows Lt=60.0229 1-e-0.2325(t+0.6108), and Wt=3261.91371-e-0.2325(t + 0.6108)3.113.The growth inflection point is at t = 4.2, corresponding to L = 41.05cm, and W = 973.03g.The data obtained infer that the fish grows much faster before 4 years of age than does after 4 years of age.The varieties of growth index also show the same trend.Based on the research results, we suggest that the catchable size of the fish from the Yangtze River should be above 1000g with the aim of rational utilization and protection for the resources of fish.