Application Of An Ecological Recycling Aquaculture System In Production Of Grass Carp Fingerling

In this study, combining technology of artificial wetland wastewater treatment and traditional pond aquaculture, one ecological recycling aquaculture system which consist of subsurface flow wetland, flow water surface wetland, fishpond, transport pipeline and control system was constructed according to ecological requirement. The purifying effects of ecological recycling aquaculture system on aquaculture wastewater, the improvement for water quality of fish pond and the fingering breeding were studied. The results are as follows.1. Under 760mm/d hydraulic loading, the average removal rate of constructed wetland for NH₄⁺-N, NO₂^--N, NO₃^--N, TN, TP, COD, TSS in aquaculture wastewater were 33.56±3.71%, 50.73±3.95%, 46.33±4.95%, 27.99±2.78%, 58.15±3.38%. 29.60±2.24% and 84.49±1.77%, respectively.2. The corresponding values in wetland water according with the national standard of water quality for fisheries. The treated pond's water quality outbalanced than that of control pond3. Within 4 months' breeding, the average length of Grass Carp fry grew to 16.3±0.2cm and 5.2±0.3g from 6.9±0.5cm and 40.5±3.7g with an average density of 20inds/m2. The output of fingering in treated pond's was 2127±27 Kg/hm², 67.80±3.65% for the survival rate. The average survival rate, output and feed coefficient of treated fishpond remarkably outweighed those reared in the control fishpond (P< 0. 05) . The ecological recycling aquaculture system had distinct superiority compared with traditional static fishpond for fingerling breeding of grass carp.4. The ecological recycling aquaculture system can improve the usage of water resource, reduce the risk of polluting water environment for drainage, the probability of getting sick and treatment is largely reduced with the fall of fishpond's pollution load, consequently, the fish quality is improved, more economical benefits and more environment benefits are produced, the ecological recycling aquaculture system belong to resource-saving and environment-friendly aquaculture mode...