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1.
Nutrient loadings are an important component of aquaculture impacts as they can lead to cascade effects at the ecosystem level. An evaluation of these effects on foodweb functioning is presented and discussed for the case study of Lake Burullus in the Nile Delta, Egypt, where semi-intensive aquaculture in earthen ponds has grown remarkably in recent decades. Estimations of nutrient loads into the lake's brackish water, from agriculture and fish ponds, were assessed. A biogeochemical model was set up and calibrated to simulate the loads from nitrogen, phosphorus and phytoplankton, with and without fish ponds. The biogeochemical model was coupled offline to a foodweb model to test the effects of additional nutrient loads from aquaculture on the lake's foodweb functioning. The results obtained by comparing the present conditions of aquaculture development with a no-aquaculture scenario allowed us to identify a set of indicators of foodweb functioning which are sensitive to changes in nutrient loads from aquaculture. The limited changes in phytoplankton concentration with respect to changes in nutrient loads suggested that primary production in Lake Burullus is presently controlled largely by factors other than nutrient influxes from aquaculture. This study emphasises the potential benefits of using a combination of biogeochemical and foodweb models to assess the cumulative effects of nutrient loading from aquaculture on a receiving water body. 相似文献
2.
《Marine Policy》2017
As shellfish aquaculture activities grow in the US, researchers, practitioners, resource users, and others have questioned how much development can be accommodated by natural and social systems. In a unique application of the normative evaluation approach to shellfish aquaculture development, this study uses data from a mail survey to (1) examine Rhode Islanders’ support for aquaculture in general and in RI waters; (2) investigate how different features of an aquaculture farm influence normative evaluations; and (3) explore areas of agreement and disagreement among stakeholder groups for social carrying capacities associated with aquaculture in RI coastal waters. Findings demonstrate that respondents do not strictly support or oppose aquaculture development; instead support depends on the waterbody where the aquaculture is occurring, the amount of area used for aquaculture, and ways in which aquaculture is conducted. Social norm curves show that levels of acceptabilities for shellfish aquaculture development in two RI waterbodies decline with increasing levels of aquaculture activities. Comparisons among sub-sets of respondents highlight disagreement among groups on the level beyond which shellfish aquaculture development is no longer acceptable (social carrying capacity). Results from normative evaluation studies can be used in combination with physical, ecological, and biological carrying capacities; management goals and objectives; other resource uses and values; and desired social and ecological conditions to inform policy discussions about shellfish aquaculture development in coastal waters. 相似文献
3.
One of the key needs of the aquaculture industry is the implementation of effective management methods to ensure the sustainability, economic viability and minimization of negative impacts on both human and ecosystem well-being. The authors developed a Fortran 90 implementation of the dynamic energy budget (DEB) model for Mytilus edulis. The model has been further developed to include physiological interactions with the ecosystem and coupled to a biogeochemical nutrient–phytoplankton–zooplankton–detritus (NPZD) model. Phytoplankton and detritus uptakes, oxygen utilisation, CO2 production, NH4 excretion, egestion of faeces, and assimilation of food are modelled. A novel approach was derived that accounts for the allocation of C and N in mussel flesh and shell organic fraction. The DEB–NPZD model has been subsequently coupled to a high resolution three dimensional numerical coastal ocean model of the south–west coast of Ireland, where approximately 80% of national rope mussel is produced annually. Simulations have been carried out for the time period July 2010–June 2011, for which the field data on mussel biometrics and ambient seawater properties were collated. The model accurately reproduced the spatio-temporal variability in blue mussel growth. It is also shown that the ecosystem dynamics is affected by the presence of aquaculture farms. The modelling system presented allows for the assessment of the impacts of aquaculture activities on water quality, quantification of the production and ecological carrying capacities and improvement of our understanding of the ecosystem functioning with particular emphasis on interactions between various trophic levels. 相似文献
4.
High rates of marine primary production, as well as most world fishery production, are confined to coastal regions. There are three categories of nutrient enrichment processes: (1) coastal upwelling, (2) tidal mixing, and (3) land-based runoff and major river outflow. These are depicted on a single map as a basis for identificaiton of groups of regional marine ecosystems that may have analogous aspects with respect to basic modes of enrichment. These groupings may provide a rational framework for comparative ecological studies. The concept of the marine catchment basin (MCB) is stressed as representing the logical unit for management of anthropogenic effects on any marine ecosystem that is substantially affected by terrestrial runoff. 相似文献
5.
One of the key concerns in estuarine and coastal environments is eutrophication, which is known to be closely connected to nutrient enrichment. To control and improve surface water quality, nutrient criteria are recommended in order to provide reference conditions for the environment. However, the current datasets of nutrient criteria in China are either designed for surface water or sea water, and as such these are not suitable for assessing estuarine water quality, especially given the unique ecosystem and dynamic properties of estuaries. To address this issue in current estuarine water management, nutrient criteria have been developed for a local estuary in the southeast of China. Segmentation of the Jiulong River Estuary, China was firstly analysed through field investigations carried out during 2013–2014, which resulted in the delineation of three segments characterized by their distinct properties in relation to salinity, hydrology, ecosystems, etc. Historical records from 1997 to 2014 were then analysed using statistical modelling to develop candidate nutrient criteria for the estuary.This stage of the analysis was undertaken in combination with the study of nutrient status records from the 1980s,which were used to establish a baseline reference condition. The recommended criteria values of dissolved inorganic nitrogen(DIN) in Segments Ⅰ, Ⅱ and Ⅲ of the Jiulong River Estuary are 64, 21 and 14 μmol/L,respectively, and the corresponding values for soluble reactive phosphorus(SRP) are 0.89, 0.76 and 0.89 μmol/L,respectively. It should be emphasised that these values are site-dependent, and that different results may be achieved at other locations depending on the physical and biogeochemical characteristics of an estuary, or even a single site within a catchment. It is hoped that by demonstrating a possible methodological approach and methods of nutrient criteria derivation in the Jiulong River Estuary, the current study will offer researchers some fundamental basis from which to begin to develop more complete nutrient criteria indices for the study of nutrient conditions in other estuaries throughout China. 相似文献
6.
本文以2013-2017年我国鱼类、甲壳类、贝类、藻类、其他类产品海水养殖规模及产量的分析为基础,有别于现有文献关于我国海水养殖业发展现状的分析,创新性地使用比较优势模型并测算专业化系数,分析我国海水养殖结构特点,明确10个沿海省市的优势海水养殖产品及其养殖专业化程度,从而有针对性地指出我国海水养殖结构的优化方向。文章结果表明:(1)我国五类海水养殖产品的产量均呈上升趋势,且贝类的产量始终最高;海水养殖总面积有所下降,其中贝类产品的养殖面积虽逐年减少,但始终位于第一。(2)山东、福建、广东三省的海水养殖总产量、养殖规模和单产均位于全国10个沿海省市的前列。(3)10个沿海省市分别拥有自己的优势海水养殖产品,但只有海南充分发挥优势实现专业化生产。对此,我国应继续优化海水养殖产品布局,促进各省市对自身比较优势产品的规模化生产,从而推动全国海水养殖产业的高效专业化发展。 相似文献
7.
Impacts of marine aquaculture at large spatial scales: evidences from N and P catchment loading and phytoplankton biomass 总被引：1，自引：0，他引：1
Sarà G Lo Martire M Sanfilippo M Pulicanò G Cortese G Mazzola A Manganaro A Pusceddu A 《Marine environmental research》2011,71(5):317-324
While several studies point at off-shore aquaculture as a possible source of impacts on the local marine environment, very few have analysed its effects at large scales such as at the bay, gulf or basin levels. Similar analyses are hampered by the multiple sources of disturbance that may concomitantly affect a given area. The present paper addresses these issues taking the Gulf of Castellammare (Southern Tyrrhenian Sea) as an example. Nitrogen (N) and phosphorous (P) loads were calculated for the period 1970-2007, and compared to chlorophyll-a concentration as measured inside and outside the Gulf over the same period. Results indicate that N and P catchment loading has constantly decreased because of improved environmental management. Nevertheless, nutrient concentration in the Gulf has steadily increased since the establishment of aquaculture facilities in 1999. Chlorophyll-a concentration followed this trend, showing a marked increase from 2001 onwards. In the same period, chlorophyll-a concentrations measured inside and outside the Gulf have significantly diverged. As all the other possible causes can be ruled out, aquaculture remains the sole explanation for the observed situation. This paper demonstrates for the first time ever that off-shore aquaculture may affect the marine ecosystem well beyond the local scale and provides an additional element of concern to be kept into consideration when allocating oceans' space for new fish-farming activities. 相似文献
8.
Environmental consequence analyses of fish farm emissions related to different scales and exemplified by data from the Baltic--a review 总被引：3，自引：0，他引：3
The aim of this work is to review studies to evaluate how emissions from fish cage farms cause eutrophication effects in marine environments. The focus is on four different scales: (i) the conditions at the site of the farm, (ii) the local scale related to the coastal area where the farm is situated, (iii) the regional scale encompassing many coastal areas and (iv) the international scale including several regional coastal areas. The aim is to evaluate the role of nutrient emissions from fish farms in a general way, but all selected examples come from the Baltic Sea. An important part of this evaluation concerns the method to define the boundaries of a given coastal area. If this is done arbitrarily, one would obtain arbitrary results in the environmental consequence analysis. In this work, the boundary lines between the coast and the sea are drawn using GIS methods (geographical information systems) according to the topographical bottleneck method, which opens a way to determine many fundamental characteristics in the context of mass balance calculations. In mass balance modelling, the fluxes from the fish farm should be compared to other fluxes to, within and from coastal areas. Results collected in this study show that: (1) at the smallest scale (<1 ha), the "footprint" expressing the impact areas of fish cage farm often corresponds to the size of a "football field" (50-100 m) if the annual fish production is about 50 ton, (2) at the local scale (1 ha to 100 km2), there exists a simple load diagram (effect-load-sensitivity) to relate the environmental response and effects from a specific load from a fish cage farm. This makes it possible to obtain a first estimate of the maximum allowable fish production in a specific coastal area, (3) at the regional scale (100-10,000 km2), it is possible to create negative nutrient fluxes, i.e., use fish farming as a method to reduce the nutrient loading to the sea. The breaking point is to use more than about 1.1 g wet weight regionally caught wild fish per gram feed for the cultivated fish, and (4) at the international scale (>10,000 km2) related to the Baltic Proper, the contribution from fish farms to the overall nutrient fluxes are very small. We have also given two case-studies at the local scale where the impact of the fish farm emissions are greatest and the idea is to identify coastal areas unsuitable and suitable for fish cage farms and the reasons why. It should also be stressed that the results presented here are exemplified using emissions from fish farms, but that the underlying principles to evaluate the ecosystem effects of nutrient discharges from point source emissions are valid in a wider and more general perspective. 相似文献
9.
10.
《Marine Policy》2017
This paper explores the seafood sector in Indonesia, using fish supply-demand modeling, with special focus on the growing role of aquaculture in the country's food portfolio. The paper describes six scenarios for future fish supply–demand dynamics and examines the role of aquaculture growth in fish supply in Indonesia. A business as usual scenario (BAU) assumed exogenous variables of our supply-demand model following historical trends. Five alternative scenarios explored the implications of stagnant capture fisheries; export-oriented growth of aquaculture; domestic-oriented aquaculture growth; slow growth of aquaculture sector; and disease outbreaks to key aquaculture species. The BAU scenario projected that fish supply and demand in Indonesia continues to increase over time and strong aquaculture growth is critical to meet increasing demand for fish. Stagnant capture fisheries resulted in increasing fish prices and decreasing fish consumption. Export-oriented aquaculture growth benefitted fish supply and exports, but also helped lower domestic prices and thus increase consumption. An emphasis on domestic aquaculture commodities increased fish supply, providing best domestic consumption outcomes and lower consumer prices. Slow aquaculture growth reduced fish supply and led to undesirable increases in domestic prices and decreasing domestic consumption as a consequence. Disease outbreaks in shrimp and carp aquaculture resulted in a short-term reduction in aquaculture output and increasing fish prices, lowering fish consumption. 相似文献
11.
The increasing global demand for animal protein is a major ecological concern due to its impacts on land use, climate change, global grain supply and fisheries. One method for harvesting animal protein is to grow marine fish. This is widely practiced in coastal environments, but also leads to environmental problems associated with habitat loss and nutrient loading. One alternative is to move marine aquaculture further offshore, away from coastal land-use conflicts and towards ocean currents, which can efficiently dispose wastes. This concept creates a logistical challenge, however, since operators have to transport large amounts of food, fish and fuel to and from offshore cages on a regular basis and in varied weather conditions. In this paper, we discuss the economic feasibility of using offshore oil and gas platforms as bases for open ocean aquaculture in the Gulf of Mexico. We develop net-present value models of a platform-based operation and describe sensitivity analysis of the model output. We conclude that offshore platform-based mariculture may be commercially viable under favorable assumptions, that its viability requires economies of scale and depends principally on the yield per unit of cage volume achieved. The limitations of the analysis are described. 相似文献
12.
近几十年来,黄海渔业资源的开发利用得到了飞速发展。作为重要的海水养殖以及海洋捕捞区域,黄海海洋生态系统为全国提供了丰富的海产品。本研究首次采用海洋供给服务评估方法研究黄海区域养殖生产和捕捞生产的物质量及价值量变化情况,结果表明：1990—2015年,黄海区域海水养殖物质量和价值量持续上升,2015年养殖物质量（883.1万t）比1990年（103.6万t）上升了752.4%,价值量则从130.1亿元上升至1 834.4亿元。与此同时,海洋捕捞物质量和价值量则呈现先上升后下降的趋势,在2000年达到顶峰（530.7万t,2 772.3亿元）后均有所下降。海水养殖价值量百分比组成变化十分显著,由最初的贝类和虾蟹类为主变为贝类（45.8%）和其他类（32.8%）为主。海洋捕捞价值量中其他类和头足类的比例也在不断增加,2015年增至24.9%,仅次于鱼类的捕捞价值量。黄海区域渔业利用变化情况与全球气候改变、近岸水域环境受污染严重以及各类养殖技术快速发展等密不可分。本研究期望通过海洋供给服务评估分析为黄海区域渔业资源利用管理以及可持续发展提供一定的科学基础。 相似文献
13.
A three-dimensional numerical model of hydrodynamics and water quality in Hakata Bay 总被引：1，自引：0，他引：1
The hydrodynamics and water quality in Hakata Bay, Japan, are strongly affected by the seasonal variations in both the gravitational circulation and the stratification in the bay. The three-dimensional hydrodynamics and water quality model has been developed to simulate the long-term transport and fate of pollutants in the system. The model is unique in that it completely integrates the refined modelling of the hydrodynamics, biochemical reactions and the ecosystem in the coastal areas. It is a 3-dimensional segmented model which is capable of resolving mean daily variations in all the parameters relevant to pollution control. It predicts daily fluctuations in the oxygen content at different depths in water throughout the year. It takes into account transport and settling of pollutant particles. It predicts light penetration from computed turbidity variations. It includes interactions between the ecosystem and water quality, through nutrient cycling and photosynthesis. The model has been calibrated well against the data set of historical water quality observations in Hakata Bay. 相似文献
14.
《Ocean & Coastal Management》2003,46(6-7):681-700
The southern Mexican states on the coast of the Gulf of Mexico produce approximately 85% of the total national oil production. The region has also attracted attention due its important economic influence in terms of fisheries, aquaculture and agriculture, and for its ecosystem diversity. The justification for more integrated approaches to aquaculture development is significant, as coastal aquaculture has brought economic and employment benefits to both national economies and coastal people. The aim of this study is the analysis of Mecoacan fishing communities’ perception on coastal resources management and to assess group awareness of the potential benefits and impacts of coastal aquaculture. Although aquaculture practices have been implemented as an alternative to fishing and to improve current levels of fisheries production, the results showed that conditions within Mecoacan fisheries have deteriorated significantly, as collective aggregation is not producing a positive outcome for the local communities. However, fishermen regarded the restructuring of fishing organisations as a means of integrating employment and income generation alternatives such as aquaculture practices. Therefore, a key to success will be to demonstrate the ability of good coastal management to promote capacity building within coastal communities in the context of a participatory intervention strategy through formal and informal organisations. 相似文献
15.
Ecosystem-based management of marine fisheries requires the use of simulation modelling to investigate the system-level impact of candidate fisheries management strategies. However, testing of fundamental assumptions such as system structure or process formulations is rarely done. In this study, we compare the output of three different ecosystem models (Atlantis, Ecopath with Ecosim, and OSMOSE) applied to the same ecosystem (the southern Benguela), to explore which ecosystem effects of fishing are most sensitive to model uncertainty. We subjected the models to two contrasting fishing pressure scenarios, applying high fishing pressure to either small pelagic fish or to adult hake. We compared the resulting model behaviour at a system level, and also at the level of model groups. We analysed the outputs in terms of various commonly used ecosystem indicators, and found some similarities in the overall behaviour of the models, despite major differences in model formulation and assumptions. Direction of change in system-level indicators was consistent for all models under the hake pressure scenario, although discrepancies emerged under the small-pelagic-fish scenario. Studying biomass response of individual model groups was key to understanding more integrated system-level metrics. All three models are based on existing knowledge of the system, and the convergence of model results increases confidence in the robustness of the model outputs. Points of divergence in the model results suggest important areas of future study. The use of feeding guilds to provide indicators for fish species at an aggregated level was explored, and proved to be an interesting alternative to aggregation by trophic level. 相似文献
16.
Interactions between a natural food web,shellfish farming and exotic species: The case of the Bay of Mont Saint Michel (France) 总被引：1，自引：0，他引：1
To ensure sustainable uses of the coastal zone, an integrated ecosystemic approach and ecosystem models are required to frame ecological processes and evaluate environmental impacts. Here, a mass-balance trophic (Ecopath) model of the Mont Saint Michel Bay (MSMB) was developed, to analyze the bay's functioning as an ecosystem. This bay, intensively exploited by fishing and for shellfish farming, is also suffering from the proliferation of the gastropod Crepidula fornicata, an exotic species. 相似文献
17.
Abigail McQuatters-Gollop Alison J. Gilbert Laurence D. Mee Jan E. Vermaat Yuri Artioli Christoph Humborg Fred Wulff 《Estuarine, Coastal and Shelf Science》2009,82(4):583-596
Anthropogenic eutrophication affects the Mediterranean, Black, North and Baltic Seas to various extents. Responses to nutrient loading and methods of monitoring relevant indicators vary regionally, hindering interpretation of ecosystem state changes and preventing a straightforward pan-European assessment of eutrophication symptoms. Here we summarize responses to nutrient enrichment in Europe's seas, comparing existing time-series of selected pelagic (phytoplankton biomass and community composition, turbidity, N:P ratio) and benthic (macro flora and faunal communities, bottom oxygen condition) indicators based on their effectiveness in assessing eutrophication effects. Our results suggest that the Black Sea and Northern Adriatic appear to be recovering from eutrophication due to economic reorganization in the Black Sea catchment and nutrient abatement measures in the case of the Northern Adriatic. The Baltic is most strongly impacted by eutrophication due to its limited exchange and the prevalence of nutrient recycling. Eutrophication in the North Sea is primarily a coastal problem, but may be exacerbated by climatic changes. Indicator interpretation is strongly dependent on sea-specific knowledge of ecosystem characteristics, and no single indicator can be employed to adequately compare eutrophication state between European seas. Communicating eutrophication-related information to policy-makers could be facilitated through the use of consistent indicator selection and monitoring methodologies across European seas. This work is discussed in the context of the European Commission's recently published Marine Strategy Directive. 相似文献
18.
Ulf Lindstrm Sophie Smout Daniel Howell Bjarte Bogstad 《Deep Sea Research Part II: Topical Studies in Oceanography》2009,56(21-22):2068
The Barents Sea ecosystem, one of the most productive and commercially important ecosystems in the world, has experienced major fluctuations in species abundance the past five decades. Likely causes are natural variability, climate change, overfishing and predator–prey interactions. In this study, we use an age-length structured multi-species model (Gadget, Globally applicable Area-Disaggregated General Ecosystem Toolbox) to analyse the historic population dynamics of major fish and marine mammal species in the Barents Sea. The model was used to examine possible effects of a number of plausible biological and fisheries scenarios. The results suggest that changes in cod mortality from fishing or cod cannibalism levels have the largest effect on the ecosystem, while changes to the capelin fishery have had only minor effects. Alternate whale migration scenarios had only a moderate impact on the modelled ecosystem. Indirect effects are seen to be important, with cod fishing pressure, cod cannibalism and whale predation on cod having an indirect impact on capelin, emphasising the importance of multi-species modelling in understanding and managing ecosystems. Models such as the one presented here provide one step towards an ecosystem-based approach to fisheries management. 相似文献
19.
《Marine Policy》2016
The Gulf of Gabes located in southern Tunisia is one of the most productive ecosystems in the Mediterranean Sea. Despite its ecological importance, it is subject to high fishing pressure affecting the different components of the ecosystem. Given the multispecies, multigear nature of the fishery, there is a need to manage trade-offs between environmental and economic objectives. In this study, an Ecospace model was developed based on the previously constructed Ecopath model of the Gulf of Gabes and calibrated for the period 1995–2008 to investigate the response of the ecosystem to a set of alternative spatial management scenarios. These scenarios were derived from the current fishery regulation owing the important interest expressed by local fishery managers to assess new management measures. The results showed for each management scenario how bottom trawling and coastal fishing impact the different trophic groups and the complexity of interaction between these two fishing activities. Furthermore, spatially explicit simulations were performed to identify regions where the management measures are effective. Results suggested that for some trophic groups, these regions are well-defined which would be interesting to propose more accurate spatial measures. Finally, several indicators were calculated to evaluate the proposed management plans and provide managers with a straightforward set of decision rules to describe the potential trade-offs and fulfill both fisheries and conservation management objectives in the context of an ecosystem approach. The decision rules were based on observed trends to reduce uncertainty relative to the model complexity and provide consistent advice to decision-makers. 相似文献
20.
To evaluate the relevance of a watershed modelling for assessing the contamination of coastal waters due to land-based sources and activities, a modelling approach, using SWAT (Soil and Water Assessment Tool) model, was implemented on the watersheds of Pen-Bé estuary and Le Croisic bay. For the past few years, various dysfunctions occurred in these shellfish farming areas located on the West coast of France. Therefore, it seemed critical to estimate the coastal watershed loadings in order to get a better understanding of the dysfunctions. In the same way, an empiric method based on water quality samplings was also carried out in order to evaluate the potential pollutant attenuation of the coastal wetlands. The results presented in this paper focus on simulated streamflows and phosphorus flows. Despite the limited existing data, which involved to integrate aggregated or averaged values for several aspects, according to the Nash and Sutcliffe efficiency criterion, the simulated flows seem close to the measurements. The simulated continuous flows appeared as a useful complement to intermittent water quality samplings and streamflow measures resulting from water monitoring networks. Moreover, by identifying the most contributory sub-watersheds, the simulations could be used to suggest priority areas of intervention for decreasing the coastal watershed loadings. 相似文献