Abstract: The survival rates of catchable groups of silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis) were calculated by means of Robson-Chapman formula, and those of noncatchable ones and population production were also estimated. The annual survival rates of noncatchable groups of the fishes were 0.25 in average, and those of catchable ones were 0.32 for silver carp and 0.38 for bighead carp. The total population production of silver carp and bighead carp was 141 and 110 kg/ha respectively. The yield of fishes was 33% and 34% of their production, and 36% of their biomass. The annual coefficients P/Bof fish populations were 1.15 and 1.09 respectively.

Key words: Reservoir, Silver carp, Bighead carp, Production