Emergy analysis is effective for analyzing ecological economic systems. However, the accuracy of the approach is af- fected by the diversity of economic level, meteorological and hydrological parameters in different r...Emergy analysis is effective for analyzing ecological economic systems. However, the accuracy of the approach is af- fected by the diversity of economic level, meteorological and hydrological parameters in different regions. The present study evalu- ated the economic benefits, environmental impact, and sustainability of indoor, semi-intensive and extensive farming systems of sea cucumber （Apostichopus japonicus） in the same region. The results showed that A. japonicus indoor farming system was high in input and output （yield） whereas pond extensive farming system was low in input and output. The output/input ratio of indoor fann- ing system was lower than that of pond extensive farming system, and the output/input ratio of semi-intensive farming system fell in between them. The environmental loading ratio of A.japonicus extensive fanning system was lower than that of indoor farming sys- tem. In addition, the emergy yield and emergy exchange ratios, and emergy sustainability and emergy indexes for sustainable devel- opment were higher in extensive farming system than those in indoor farming system. These results indicated that the current exten- sive farming system exerted fewer negative influences on the environment, made more efficient use of available resources, and met more sustainable development requirements than the indoor farming system. A. japonicus farming systems showed more emergy benefits than fish fanning systems. The pond fanning systems ofA. japonicus exploited more free local environmental resources for production, caused less potential pressure on the local environment, and achieved higher sustainability than indoor farming system.展开更多
The economic viability and social value of traditional aquaculture in rural Sierra Leone were evaluated. The hypothesis tested was that traditional methods of farming fish in ponds were not economically viable, so far...The economic viability and social value of traditional aquaculture in rural Sierra Leone were evaluated. The hypothesis tested was that traditional methods of farming fish in ponds were not economically viable, so farmers were investing their time/labour in less risky and more profitable livelihoods activities. The assumption in this assessment was that fish farming is an economic activity, and that for farmers to adopt or choose it over other livelihoods, the benefit-cost ratio of fish farming must be higher than that of alternative livelihoods. The main objective of the study was to assess why local farmers failed to adopt modem market oriented aquaculture production systems introduced by the Ministry of Fisheries and Marine Resources in rural Sierra Leone. Two hundred farmers owning fishponds on family lands were interviewed using semi-structured questionnaires and farmers＇ responses were analyzed using statistical tools （SPSS 16.0）. The mean contributions of different livelihoods to total annual incomes of farmers and the social values they attached to these livelihoods were compared. Results of the study suggested that traditional fish fanning was economically viable across the range of pond sizes sampled; but the medium-sized ponds were more profitable than the smallest and largest ponds, and labour accounted for 70% of total annual production costs in the systems assessed. The average benefit-cost ratio of 2.3 for fish fanning was favorable compared with that of 0.83 for rice farming, which was ranked as most popular livelihood activity by farmers. The payback period for traditional aquaculture investments was less than five years using informal investment loans （without interest）, and was favorably compared with that for tree crops fanning, which was also popular among farmers. Additional benefits of fish fanning included social capital and maintenance of kinship relationships.展开更多
At present, the marine environment is faced with extremely serious eutrophication. The kelp＇s ability of taking in nitrogen and phosphorus can be fully performed so that the eutrophication problem can be effectively ...At present, the marine environment is faced with extremely serious eutrophication. The kelp＇s ability of taking in nitrogen and phosphorus can be fully performed so that the eutrophication problem can be effectively treated and solved. Based on the analysis of kelp＇s absorption of nutritive salt from aquaculture sewage, this paper further explores the bioremediation of kelp in aquaculture sea area with eutrophication in the hope of providing valuable reference for the aquaculture industry of BohaiSea.展开更多
基金supported by the Key R & D Program (2011BAD13B03)the National Marine Public Welfare Project of China (200905020)the program for Excellent Youth Foundation of Shandong province (Grant No. JQ201009)
文摘Emergy analysis is effective for analyzing ecological economic systems. However, the accuracy of the approach is af- fected by the diversity of economic level, meteorological and hydrological parameters in different regions. The present study evalu- ated the economic benefits, environmental impact, and sustainability of indoor, semi-intensive and extensive farming systems of sea cucumber （Apostichopus japonicus） in the same region. The results showed that A. japonicus indoor farming system was high in input and output （yield） whereas pond extensive farming system was low in input and output. The output/input ratio of indoor fann- ing system was lower than that of pond extensive farming system, and the output/input ratio of semi-intensive farming system fell in between them. The environmental loading ratio of A.japonicus extensive fanning system was lower than that of indoor farming sys- tem. In addition, the emergy yield and emergy exchange ratios, and emergy sustainability and emergy indexes for sustainable devel- opment were higher in extensive farming system than those in indoor farming system. These results indicated that the current exten- sive farming system exerted fewer negative influences on the environment, made more efficient use of available resources, and met more sustainable development requirements than the indoor farming system. A. japonicus farming systems showed more emergy benefits than fish fanning systems. The pond fanning systems ofA. japonicus exploited more free local environmental resources for production, caused less potential pressure on the local environment, and achieved higher sustainability than indoor farming system.
文摘The economic viability and social value of traditional aquaculture in rural Sierra Leone were evaluated. The hypothesis tested was that traditional methods of farming fish in ponds were not economically viable, so farmers were investing their time/labour in less risky and more profitable livelihoods activities. The assumption in this assessment was that fish farming is an economic activity, and that for farmers to adopt or choose it over other livelihoods, the benefit-cost ratio of fish farming must be higher than that of alternative livelihoods. The main objective of the study was to assess why local farmers failed to adopt modem market oriented aquaculture production systems introduced by the Ministry of Fisheries and Marine Resources in rural Sierra Leone. Two hundred farmers owning fishponds on family lands were interviewed using semi-structured questionnaires and farmers＇ responses were analyzed using statistical tools （SPSS 16.0）. The mean contributions of different livelihoods to total annual incomes of farmers and the social values they attached to these livelihoods were compared. Results of the study suggested that traditional fish fanning was economically viable across the range of pond sizes sampled; but the medium-sized ponds were more profitable than the smallest and largest ponds, and labour accounted for 70% of total annual production costs in the systems assessed. The average benefit-cost ratio of 2.3 for fish fanning was favorable compared with that of 0.83 for rice farming, which was ranked as most popular livelihood activity by farmers. The payback period for traditional aquaculture investments was less than five years using informal investment loans （without interest）, and was favorably compared with that for tree crops fanning, which was also popular among farmers. Additional benefits of fish fanning included social capital and maintenance of kinship relationships.
文摘At present, the marine environment is faced with extremely serious eutrophication. The kelp＇s ability of taking in nitrogen and phosphorus can be fully performed so that the eutrophication problem can be effectively treated and solved. Based on the analysis of kelp＇s absorption of nutritive salt from aquaculture sewage, this paper further explores the bioremediation of kelp in aquaculture sea area with eutrophication in the hope of providing valuable reference for the aquaculture industry of BohaiSea.
