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261.
The New York Bight is perhaps one of the most used and abused coastal areas in the world as a consequence of urbanization and the disposal of the waste of some 20 million people who reside by its shores and surrounding bays and estuaries. A variety of sources, including those associated with sewage wastes, industrial wastes, contaminated dredged material, urban runoff, and atmospheric fallout contaminate these coastal waters. Many of the stresses of excess population and industrialization as measured by pollutant loadings and ecosystem impacts can be crudely quantified in terms of use impairments-use impairments that have measurable social and economic relevance. Five broad categories of impairment attributed to pollution in the Bight that are causing significant losses of ecological, economic, or social values are: beach closures, unsafe seafoods, hazards to commercial and recreational navigation, loss of commercial and recreational fisheries, and declines in birds, mammals and turtles. These impairments are generally caused by floatable wastes, nutrients, toxicants, pathogens and habitat loss. Measures of such impairments are not standard, nor in many cases totally quantifiable. We have examined specific subsets of these impairments in terms of their spatial and temporal changes and as a first approximation determined the economic and social significance of these changes. the cost of these impaired uses of the Bight are measured in terms of billions of dollars annually for New York and New Jersey. 相似文献
262.
263.
太湖渔业环境优化技术初探 总被引:1,自引:1,他引:0
根据对东太湖养殖区主要水化学指标进行的跟踪监测结果,系统分析研究了N、P等主要营养物质的变化趋势。结果显示,TP网围内的周年平均值为0.034mg/L,网围外周年平均值为0.042mg/L,TN网内周年平均值为0.72mg/L,网外周年平均值为0.73mg/L。并依据试验及监测结果,估算了太湖养殖渔业对水体的营养贡献份额(N、P),现有养殖状况每年通过水产品可带出湖中19.51tN和6.62tP。通过调整、优化养殖模式,大力推广应用轮牧式网围养殖,大幅降低放养量,合理搭配滤食性鱼类,在养殖区普及种植太湖优势水生植物,移植本湖底栖动物,利用水生植物和底栖动物既可有效净化养殖环境,又能作为养殖对象的适口饲料这种作用和功能,同时充分利用湖区低值鱼资源作为河蟹的饲料,最终将水草、螺、低值鱼等转化成水产品,并通过水产品的形式将营养物质带出湖区,从而达到优化改善渔业环境的目的。 相似文献
264.
南水北调东线工程对长江口渔业资源的影响 总被引:5,自引:0,他引:5
董方勇 《长江流域资源与环境》1997,6(2):168-172
工程在5-10月份调水,对长江口鱼,虾,蟹类影响极小。在11-4月份调水,对长江口鱼,虾,蟹类略有影响,海水鱼类的数量将有所增加,淡水鱼类和半咸水鱼类的分布范围将向口内扩展,刀鲚,前颌间奶鱼和凤鲚向长江口作生殖洄游的时间将有所推迟,安氏长臂虾,脊尾长臂虾的分布和中华绒螯蟹的产卵场将向口内偏移。 相似文献
265.
Didier?RobertEmail author Antoine?Piscopo Jean-Victor?Weber 《Environmental Chemistry Letters》2004,2(1):5-8
Photocatalytic reactions using titanium dioxide are of great interest due to their possible applications to solar energy storage and detoxification of wastewater. However, TiO2 has usually given a very poor selectivity. Here we show that, using binary mixtures, it is possible to selectively degrade one molecular substance without any concentration change of another substance. We have studied the influence of the pH and TiO2 concentration on the selectivity of the degradation of benzamide and 4-hydroxybenzoic acid. With appropriate modifications of both parameters, the selectivity can be improved. 相似文献
266.
The New York Bight is perhaps one of the most used and abused coastal areas in the world as a consequence of urbanization and the disposal of the waste of some 20 million people who reside by its shores and surrounding bays and estuaries. A variety of sources, including those associated with sewage wastes, industrial wastes, contaminated dredged material, urban runoff, and atmospheric fallout contaminate these coastal waters. Many of the stresses of excess population and industrialization as measured by pollutant loadings and ecosystem impacts can be crudely quantified in terms of use impairments-use impairments that have measurable social and economic relevance. Five broad categories of impairment attributed to pollution in the Bight that are causing significant losses of ecological, economic, or social values are: beach closures, unsafe seafoods, hazards to commercial and recreational navigation, loss of commercial and recreational fisheries, and declines in birds, mammals and turtles. These impairments are generally caused by floatable wastes, nutrients, toxicants, pathogens and habitat loss. Measures of such impairments are not standard, nor in many cases totally quantifiable. We have examined specific subsets of these impairments in terms of their spatial and temporal changes and as a first approximation determined the economic and social significance of these changes. the cost of these impaired uses of the Bight are measured in terms of billions of dollars annually for New York and New Jersey. 相似文献
267.
Jason K. Levy D. Marc Kilgour Keith W; Hipel 《Journal of the American Water Resources Association》2006,42(6):1451-1463
Abstract: Recognition is growing that fisheries must be both ecologically and commercially sustainable. The bioeconomic models proposed herein constitute an analytic framework capable of integrating the ethics and Societal values associated with fisheries preservation. Specifically, we focus on the normalized optimal (equilibrium) fish population, z*, a dimensionless variable representing biomass as a proportion of environmental capacity. We model z* as a function of (a) the dimensionless "bionomic growth ratio", γ, which is the ratio of the discount rate to the intrinsic population growth rate, and (b) the preservation coefficient, Ω, which is the ratio of the preservation value (a measure of Society's value for the stock) to price, assuming that the population growth rate and intrinsic growth rate are fixed. It is shown that increasing Ω significantly impacts z*, particularly for moderate values of γ (2 γ 4). Finally, stochastic population models are used to analyze the risk of a fish stock collapse due to harvesting pressures. The bioeconomic models and simulations herein described improve the accuracy and reliability of maximum sustainable yield management. 相似文献
268.
Yongxin Zhang Yanping Yang Yue Gong Ying Wang Xuecheng Wu Zhiying Zhou Weiguo Weng 《环境科学学报(英文版)》2023,123(1):212-221
Vessel emissions have contributed a great deal to air quality deterioration in China. Hence,the Chinese government has promulgated a series of stringent emission regulations. It is in this context that vessel emission control technology research is in full swing. In particular,during the 13th Five-Year Plan, the air pollution control technology of vessels has greatly improved. Vessel emission control has followed two main governance routes: source emission reduction and aftertreatment technology... 相似文献
269.
Contrasting Global Trends in Marine Fishery Status Obtained from Catches and from Stock Assessments 总被引:2,自引:0,他引:2
TREVOR A. BRANCH OLAF P. JENSEN DANIEL RICARD YIMIN YE RAY HILBORN 《Conservation biology》2011,25(4):777-786
Abstract: There are differences in perception of the status of fisheries around the world that may partly stem from how data on trends in catches over time have been used. On the basis of catch trends, it has been suggested that about 70% of all stocks are overexploited due to unsustainable harvesting and 30% of all stocks have collapsed to <10% of unfished levels. Catch trends also suggest that over time an increasing number of stocks will be overexploited and collapsed. We evaluated how use of catch data affects assessment of fisheries stock status. We analyzed simulated random catch data with no trend. We examined well‐studied stocks classified as collapsed on the basis of catch data to determine whether these stocks actually were collapsed. We also used stock assessments to compare stock status derived from catch data with status derived from biomass data. Status of stocks derived from catch trends was almost identical to what one would expect if catches were randomly generated with no trend. Most classifications of collapse assigned on the basis of catch data were due to taxonomic reclassification, regulatory changes in fisheries, and market changes. In our comparison of biomass data with catch trends, catch trends overestimated the percentage of overexploited and collapsed stocks. Although our biomass data were primarily from industrial fisheries in developed countries, the status of these stocks estimated from catch data was similar to the status of stocks in the rest of the world estimated from catch data. We conclude that at present 28–33% of all stocks are overexploited and 7–13% of all stocks are collapsed. Additionally, the proportion of fished stocks that are overexploited or collapsed has been fairly stable in recent years. 相似文献
270.