AN ESTIMATION OF THE POTENTIAL PRODUCTIVITY AND STOCKING RATE OF FINGERLINGS OF SILVER AND BIGHEAD CARPS IN DONG HU BY MEANS OF PHYTOPLANKTON PRODUCTION

The potential fish productivity of Dong Hu according to the method of energybudget, the food supplying capacity of phytoplankton for the silver and bighead carpsand their conversion rate, and the potential productivity of the two species and therational stocking rate of their fingerlings are estimated. The annual net production of phytoplankton of Dong Hu is 80% of its grossproduction, offering a food-supplying capacity of 10, 025 tons of oxygon, or 35, 188×10~6 Kcal., equal to 61,153 tons (fresh weight) of phytoplankton. The food coefficient of phytoplankton (fresh weight) for the silver and bigheadcarps is 82 and 47 respectively, and the energy conversion coefficient is 39.18 and22.69 respectively. The potential annual production of the silvar and bighead carps of Dong Hu mayreach to 1, 368, 000 kg i. e. 789 kg/ha, or more. The number of silver and bighead carps fingerlings not less than 13.3 cm inlength to be stocked each year should be 2, 090,000 and 1, 100, 000 respectively.