Ecologicai And Economic Analysis And Evaluation Of Grass Carppond Recirculating Aquaculture System

Traditional freshwater ponds are the main mode of production,a large farming area,which accounts for about 42%of the freshwater aquaculture area,and its production accounts for about 70.6 percent of total output.Traditional ponds at this stage have encountered many difficulties due to water pollution,low survival rate,increased incidence,as well as the nutrients issue of a serious waste of water,has become increasingly hindered the development of fisheries.In this case a urgent needed new models,both in the case of low cost,they can keep the water clean,it can better suit the needs of future ponds.Within the United States recirculating aquaculture ponds mode is a mode in line with the concept of modern culture,pond circulating water aquaculture ponds mode is the traditional "backyard" model of open innovation as pond water cycle "captive" mode,only help control emissions,but also turning waste into treasure,to achieve the goal of zero emissions,and easy to manage,with ecological and economic double benefit.The United States an efficient mode into China,with China’s actual studies,this test is on the ecological and economic benefits of pond recirculating aquaculture system analysis and evaluation,specific research in the following aspects.Pond recirculating aquaculture system for TP,TN,NH3-N,NO2--N,CODMn,Chla,average removal rates were 25.25%,28.24%,20.15%,16.47%,13.07%,24.54%,the removal of system is not particularly significant.From the nutritional status index,when stocking in April 22,April 22 in the nutritional status of nutritional status,September 22 sampling,the sampling points 1,sampling points 2,sampling points 3,sampling points 4 are mild eutrophication,and sampling points 5 and 6 of sampling points in the nutritional status,reflecting the purification of water area has water quality in the cycle,at each sampling point on December 22,the average point is in rich nutritional status,it can explain the pond as a whole is showing more and more of the state of nutrition,environment has become increasingly subject to the risk of pollution,when the system is running,at the same sampling time,from each sampling point of view,from the sampling point 1,sampling point 2,sampling point 3,sampling point 4,the sampling points 5,sampling points 6,flow tank inlet(sampling point 6)is less than the degree of nutrient flow pool outlet(sampling point 4)the degree of eutrophication,description water district does have a role in water purification.Grass carp pond recirculating aquaculture system planktonic algae is the most important primary producers,phytoplankton has been the most direct reflection of the environment nutritional status.Analyzing diversity of the system,in April 22,September 22 and December 22 Shannon-Weaver,R.Margalef,evenness index e shows a decreasing trend,indicating that as the system running,more and more serious water is pollution.The same sampling time,each sampling point Shannon-Weaver,R.Margalef,evenness index e is different,mainly in the sampling points 4 and 6 sampling points,sampling point 4 is lower than sampling point 6,and the reasons are stocking silver carp and other filter-feeding fish and carnivorous fish stocks,in favor filter-feeding fish water purification,Generally speaking,when the diversity index is higher,the quality is better.The grass carp is generally at a loss,due to a lower overall price in 2015,in exploring water grass carp breeding technology,the FCR of grass carp is averagely 1.65,with a total investment 438,215 Yuan,gross income 455,653.6 Yuan,net profit of 17,438.6 Yuan,and investment return rate of 4%.Grass carp FCR of traditional breeding pond about 1.8-2.2,if traditional carp pond aquaculture production is sold as the price of this year,the traditional pond net profit is about 15,336 Yuan,pond water cycling of economic benefit is higher than the traditional grass carp ponds 12.06%,has some advantages,but not obvious.In this experiment,the study of water quality and purification effect of change and phytoplankton of carp pond recirculating aquaculture system,through appropriate indicators to analyze the purifying effect and nutrition as well as the degree of pollution of the system,thereby evaluating the ecological effects of the system,in general,the system has ecological benefits compared to traditional breeding ponds,but is not obvious,and there is contamination;through economic analysis of the system evaluates economic benefit of the system,due this year grass carp prices are generally low,resulting in a loss,but if at the normal price(14-15 Yuan/kg),compared to traditional pond,the system has enormous economic benefit.