THE COMPREHENSIVE EVALUATION OF THE BENEFITS ON THE ECOLOGICAL FISHERY IN THE TYPICAL BAYS OF THE THREE GORGES RESERVOIRAN EXAMPLE OF THE GANJING RIVER WATER RANCH IN ZHONGXIAN COUNTY OF CHONGQING

This paper takes Ganjing River water ranching in Zhong Xian county of Chongqing for example to evaluate the comprehensive benefits of ecological fishery in typical bay of the Three Gorges Reservoir. Ganjing River water ranching water area is 8 hm2, the operation mode is zero feeding and grazing extensive farming, the harvesting size of Hypophthalmichthys molitrix and Aristichthys nobilis in water ranching were (2436.2486.6) g and (2769.4496.5) g, respectively, the age class of them were 3 and 4 years. In ecological benefits, the number of native fish inside and outside water ranching was 10, and the dominant species inside and outside water ranching were Hemiculter bleekeri and Pseudobrama simoni. In June, September and December, total nitrogen (TN) and total phosphorus (TP) inside the waters ranching were all lower than that of the water ranching outside or equivalent, indissolved oxygen (DO) inside the waters ranching was higher than that of water ranching outside or equivalent. In March, September and December, there was no difference in water quality between outside and inside water ranching. But in the fast growing season of fish in June, water quality inside waters ranching was better than outside water ranching, indicating that ecological fishery improved water quality. In economic benefit, the average annual benefit of Ganjing River water ranching was 2026000 RMB. In social benefit, because the construction and operation of Ganjing River water ranching, 111 fishermen changes the line of production, and it also provided 45 jobs and the average annual income of one person was 36610 RMB. It should be summed up the ecological fishery of Zhong Xian county water ranching, to extend the industrial chain, and to be popularized and applied in other bay of Three Gorges Reservoir.