THE ALTERATION AND RATIONAL UTILIZATION OF MEGALOPA RESOURCES OF ERIOCHEIR SINENSES POPULATION IN CHANGJIANG RIVER ESTUARY

Abstract:

On the basis of investigated data of crab and megalopa yield and of environ mental factors, the simple Ricker stock-recruitment model, R = 9. 583P exp (-0.001406P) was obtained. The optimum index of spawning stocks is 711. 2. In the meantime, the Ricker model including variation of environmental factors was given below. Rt = (55. 847 -1 6. 122X,1(t ) - 32. 100X2 (t ) - 56. 460X3 (t ) 29. 471X4 (t) )Pt exp (- 0.001406Pt), Where Rt as index of recruitment, Pt as index of spawning stock, X1 as index of average water temperature in May, X2 as index of average water temperature from March to May, X3 as index of average runoff from last December to March in this year , and X4 as index of average runoff in May. The seriousness of present resources of Chinese mitten-handed crab and its megalopa was discussed. Some regulatory methods of resuming and protecting the crab resources,making rational utilization of resources of nature megalopa and prospering this fishery in Changjiang river estuary were suggested.