| In twenty-first Century, the rapid development of science and technology,population expansion, resource consumption, which results in the non-renewableresources gradually reduced, so people pay more and more attention to thedevelopment and utilization of marine. China also faces serious problem of theresources shortage to constrain economic development. The sea gradually becomesthe foundation to support the sustainable development of economy and society inchina. In the twelfth “Five Year Plan”, the strategy of "To promote the development ofmarine economy" was forward. The development and utilization of marine resources,is significant to alleviate problems of national energy security, food security andresource security.With the decrease of world fishery resources, the advantage of aquaculturegradually highlights. From last century80’s, aquaculture was gradually paid moreattention in many countries, the proportion of aquaculture production increasedsignificantly. In2010, the amount of aquaculture exceeded the amount of fishing inChina. Thus, aquaculture industry plays a more important role in China and even theworld aquaculture.Mariculture areas in this study is located in Zhejiang province, Zhoushan city,Zhong-jieshan islands, which is composed of Huang Xing Island, Temple Lake Island,Qing bang Island, West Fushan, East Fushan. Current is complex, not only in thecontrol of the Yangtze River and Qiantang River, but also in the convergence impactof the Yellow Sea south-down coastal current-Yellow Sea water mass and north-upTaiwan warm current, which brings a large number of nutrients to the maricultureareas.In this study, considering the fuzziness existing in the assessment of sea waterquality of Dongji large yellow croaker breeding areas, the fuzzy comprehensiveevaluation method was used to evaluate the water quality, in order to find the factorsthat affect water quality; In addition, the emergy index system established on emergytheory,was used to analyze material flow and energy flow in the large yellow croakerbreeding areas in Dongji, in order to evaluate the sustainable development of the farming areas. Using the following two methods to analyze the present situation oflarge yellow croaker breeding areas and it’s long-term development.Based on fuzzy comprehensive evaluation method, the result of water qualitystatus in2009-2012, is four years all belong to class one in large yellow croakerbreeding areas. The overall status of the water quality is good, which is suitable forlarge yellow croaker breeding. However, in further analysis, the membership degreesto class1of each monitoring month are obvious different. Based on the emergy theory,the emergy evaluation index system is applied to characterize the environmentalimpact and the overall sustainability of the studied areas. The results showed that theTR of large yellow croaker mariculture areas is1.46×106sej/J, which was in themiddle of three aquaculture system surrounding the Pearl River Estuary, but lowerthan the average value of systems studied before. The EPD of large yellow croakermariculture areas is2.07×1017sej/ha·a, and ELR is91.10. And in this study,purchased external resource emergy inputs achieved a greater effect than puttingrenewable environmental resource emergy in large yellow croaker mariculture areas.And results showed the areas had more dependence on purchasing external resourceemergy inputs. The ESI is0.011, EISD is0.02, which indicate that the large yellowcroaker mariculture areas is less sustainable.A comprehensive analysis of the factors, forage is the factor which influents boththe status of large yellow croaker breeding areas and long-term sustainabledevelopment. Based on fuzzy comprehensive evaluation method, the water qualitystatus assessment of Dongji mariculture areas shows the content of inorganic nitrogenand inorganic phosphorus is significantly increased in June. After June, the contentwould be slightly higher than that in April and May, which may be related to breedingin Dongji large yellow croaker mariculture areas. Every year in June, the companypurchases fingerling and feeds them in cage. Forage cannot be ingested completelyand high density、 large-scale aquaculture are reasons which result in inorganicnitrogen and inorganic phosphorus increased. In addition, the emergy analysis results:the factor affecting the sustainable development of the large yellow croakermariculture areas, is non-renewable resource forage inputs, which accounts for27.17%, in second. This is one of the important factors in relationship to the lower sustainable development of mariculture areas. Therefore, forage is not only thefactor influencing the current water quality situation, but also affecting the sustainabledevelopment of mariculture areas. In this paper, countermeasures are given to solvethe final effect of forage on the environment:1) to determine the right quantity offorage;2) to improve the forage utilization rate. |
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