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51.
Abstract:  Ecosystem-scale networks of marine protected areas (MPAs) are important conservation tools, but their effectiveness is difficult to quantify in a time frame appropriate to species conservation because of uncertainties in the data available. The dugong ( Dugong dugon ) is a mobile marine species that occurs in shallow inshore waters of an ecosystem-scale network of MPAs (the Great Barrier Reef World Heritage Area [GBRWHA]). We developed a rapid approach to assess risk to dugongs in the region and evaluate options to ameliorate that risk. We used expert opinion and a Delphi technique to identify and rank 5 human factors with the potential to adversely affect dugongs and their sea grass habitats: netting, indigenous hunting, trawling, vessel traffic, and poor-quality terrestrial runoff. We then quantified and compared the distribution of these factors with a spatially explicit model of dugong distribution. We estimated that approximately 96% of habitat of high conservation value for dugongs in the GBRWHA is at low risk from human activities. Using a sensitivity analysis, we found that to decrease risk, commercial netting or indigenous hunting had to be reduced in remote areas and the effects of vessel traffic, terrestrial runoff, and commercial netting had to be reduced in urban areas. This approach enabled us to compare and rank risks so as to identify the most severe risks and locate specific sites that require further management attention.  相似文献   
52.
《Environmental Hazards》2013,12(5):446-458
ABSTRACT

Globally, fisheries are important economic resources and support many coastal communities, but the people that rely on fishing experience a range of environmental hazards. This research surveyed 300 fishing households on Kutubdia Island, Bangladesh, regarding their fishing activities and the conditions and perceptions of risk while fishing at sea. This is an artisanal fishery of small boats used for day trips, and larger but still simple boats used for multi-day trips farther offshore. Many households (62%) reported sickness or health problems while at sea. Medicine or first aid kits are carried by only 35% of the boats. Hazards encountered at sea included bad weather (69%), pirates (60%), unfriendly encounters with larger boats (20%), and engine failure (13%). The 300 households reported that 109 fishers had been lost at sea during the past 21 years. From this we estimate an annual death rate of 1335 per 100,000 fishers here, making it among the most dangerous in the world. Bangladesh needs a regulatory framework for its fisheries to include environmental, economic, political, cultural, and social components. Such a regulatory arrangement would support the Kutubdia fishers and should be incorporated into Bangladesh’s national policy for achieving its sustainability goals.  相似文献   
53.
In this issue of Environmental Management, Glenn and others posit that a previous study had analytical and interpretive errors in analysis of shrimp fishing in the Upper Gulf of California, Mexico. Unfortunately, much of their evidence is too indirect and of insufficient scale to address the central question of salinity in the Upper Gulf. Also, many of their suppositions did not include direct interviews with local officials or a robust understanding of remote sensing literature. This response to their rebuttal presents a set of figures and analysis demonstrating that the Colorado River flows into a closed evaporative basin known as the Laguna Salada and thus cannot flow into the Gulf of California. Readers are asked to examine the images and interpret their meaning for themselves.  相似文献   
54.
The key to the conservation of harvested species is the maintenance of reproductive success. Yet for many marine species large, old, individuals are targeted despite their disproportionate contribution to reproduction. We hypothesized that a combination of no-take marine protected areas (MPAs) and harvest slot limits (maximum and minimum size limits) would result in the conservation of large spawning individuals under heavy harvest. We tested this approach under different harvest intensities with a 2-sex, stage-structured metapopulation model for the Caribbean spiny lobster (Panulirus argus). P. argus is intensively harvested in the Caribbean, and in many localities large, mature individuals no longer exist. No-take MPAs and harvest slot limits combined, rebuilt and maintained large mature individuals even under high harvest pressure. The most conservative model (a 30% MPA and harvest slot limit of 75–105 mm) increased spawner abundance by 5.53E12 compared with the fishing status quo at the end of 30 years. Spawning stock abundance also increased by 2.76–9.56E12 individuals at a high harvest intensity over 30 years with MPAs alone. Our results demonstrate the potential of MPAs and harvest slot limits for the conservation of large breeding individuals in some marine and freshwater environments. Decisions on which management strategy best suits a fishery, however, requires balancing what is ecologically desirable with what is economically and socially feasible.  相似文献   
55.
舟山渔场及邻近海域桡足类种类组成和数量分布   总被引:2,自引:0,他引:2  
根据2006年8月(夏)、2007年1月(冬)、5月(春)和11月(秋)4个季节在舟山渔场及邻近海域(29°30'~31°30'N,124°30'E以西)开展海洋生态系统综合调查所获得的资料,分析了该海域桡足类的种类组成和数量分布特征。结果表明,该次调查海域共鉴定桡足类65种,其中:4个季节皆出现的种类有10种,占总种数的15.38%。优势种为中华哲水蚤(Calanus sinicus)、精致真刺水蚤(Euchaeta concinna)、微刺哲水蚤(Canthocalanus paupe)和缘齿厚壳水蚤(Scolecithrix nicobarica)等10种。根据优势度和回归贡献分析表明,春、夏、秋、冬4个季节总丰度分布主要取决于中华哲水蚤、精致真刺水蚤、缘齿厚壳水蚤和微刺哲水蚤的分布,且优势种季节更替显著。桡足类丰度高值区位于不同水系交汇的混合水域,4个季节丰度平均值变化为春季(567.4 ind·m-3)>夏季(104.12 ind·m-3)>秋季(97.23 ind·m-3)>冬季(72.45 ind·m-3)。  相似文献   
56.
Illegal, unregulated, and unreported (IUU) fishing poses a major threat to effective management of marine resources, affecting biodiversity and communities dependent on these coastal resources. Spatiotemporal patterns of industrial fisheries in developing countries are often poorly understood, and global efforts to describe spatial patterns of fishing vessel activity are currently based on automatic identification system (AIS) data. However, AIS is often not a legal requirement on fishing vessels, likely resulting in underestimates of the scale and distribution of legal and illegal fishing activity, which could have significant ramifications for targeted enforcement efforts and the management of fisheries resources. To help address this knowledge gap, we analyzed 3 years of vessel monitoring system (VMS) data in partnership with the national fisheries department in the Republic of the Congo to describe the behavior of national and distant-water industrial fleets operating in these waters. We found that the spatial footprint of the industrial fisheries fleet encompassed over one-quarter of the Exclusive Economic Zone. On average, 73% of fishing activity took place on the continental shelf (waters shallower than 200 m). Our findings highlight that VMS is not acting as a deterrent or being effectively used as a proactive management tool. As much as 33% (13% on average) of fishing effort occurred in prohibited areas set aside to protect biodiversity, including artisanal fisheries resources, and the distant-water fleet responsible for as much as 84% of this illegal activity. Given the growth in industrial and distant-water fleets across the region, as well as low levels of management and enforcement, these findings highlight that there is an urgent need for the global community to help strengthen regional and national capacity to analyze national scale data sets if efforts to combat IUU fishing are to be effective.  相似文献   
57.
The adoption of environmentally sustainable techniques by cooperatives and small companies results in specific difficulties rarely discussed in the literature. This paper describes an action-research carried out by seafood cultivators and university researchers in Guanabara Bay, which resulted in the substitution of the previous technique, based on extraction, by one without negative environmental impacts. The economic results have been satisfactory, so it can be expected that this activity may become more widespread in the region.  相似文献   
58.
Increased efforts to analyze the human dimensions of anglers are necessary to improve freshwater fisheries management. This paper is a comparative analysis of urban and rural anglers living in a metropolis, based on n = 1061 anglers responding to a mail survey in the German capital of Berlin. More than two thirds of the anglers (71%) had spent most (>50%) of their effort outside the city borders of Berlin and thus were categorized as rural anglers. Compared to the rural anglers, urban anglers (50% of total effort spent inside the city) were younger and less educated. Urban anglers were more avid and committed, less mobile, and more frequently fished from boats and during weekdays. Rural anglers were more experienced, fished for longer times per trip, fished more often at weekends and on holidays, were more often members of angling clubs, and more frequently caught higher valued fish species. The achievement and fish quantity aspects of the angling experience were more important for urban than for rural anglers. Concerning management options, urban anglers more frequently suggested constraining other stakeholders and reducing regulations, whereas rural anglers more often proposed improving physical access to angling sites. Future urban fishing programs should offer ease of access, connection to public transportation, moderate prices, and diverse piscivorous fish stocks. In contrast to rural fisheries, the provision of high ecological and aesthetical quality of the angling waters can be regarded as of minor importance in urban fisheries. Rural fisheries managers need to consider the needs of stakeholders living in Berlin to minimize impacts on the less degraded rural water bodies and potential user conflicts with resident anglers. Ecosystem-based management approaches should guide rural fisheries policy.  相似文献   
59.
Issues,impacts, and implications of shrimp aquaculture in Thailand   总被引:11,自引:0,他引:11  
Water quality impacts to and from intensive shrimp aquaculture in Thailand are substantial. Besides the surface and subsurface salinization of freshwaters, loadings of solids, oxygen-consuming organic matter, and nutrients to receiving waters are considerable when the cumulative impacts from water exchange during the growout cycle, pond drainage during harvesting, and illegal pond sediment disposal are taken into account. Although just beginning to be considered in Thailand, partial recirculating and integrated intensive farming systems are producing promising, if somewhat limited, results. By providing on-site treatment of the effluent from the shrimp growout ponds, there is less reliance on using outside water supplies, believed to be the source of the contamination.The explosion in the number of intensively operated shrimp farms has not only impacted the coastal zone of Thailand, but has also resulted in an unsustainable aquaculture industry. Abandonment of shrimp ponds due to either drastic, disease-caused collapses or more grandual, year-to-year reductions in the productivity of the pond is common. To move Thailand towards a more sustainable aquaculture industry and coastal zone environment, integrated aquaculture management is needed. Components of integrated aquaculture management are technical and institutional. The technical components involve deployment of wastewater treatment and minimal water-use systems aimed at making aquaculture operations more hydraulically closed. Before this is possible, technical and economic feasibility studies on enhanced nitrification systems and organic solids removal by oxidation between production cycles and/or the utilization of plastic pond liners need to be conducted. The integration of semi-intensive aquaculture within mangrove areas also should be investigated since mangrove losses attributable to shrimp aquaculture are estimated to be between 16 and 32% of the total mangrove area destroyed betweeen 1979 and 1993.Government policy needs to devote as much attention to sustainability issues as it has on promoting intensive pond culture. Such a balanced policy would include training and education monitoring and enforcement, rehabilitating abandoned ponds, managing land use within the coastal zone, more community involvement, and government reorganization to eliminate overlapping jurisdictions among agencies.As integrated aquaculture management becomes more the practice than the exception, less risk of crop failure to the industry and reduced discharge loadings from intensively managed shrimp ponds to receiving waters can be expected. Projected limitations on growing and marketing shrimp in the future, such as scarcity of land and broodstock, continued disease outbreaks, negative publicity, regulatory enforcement, water treatment and solids disposal costs, and increased competition from growers in other Asian countries will also drive the government and the industry towards adopting integrated aquaculture management.The data for this paper was obtained while the senior author was a Visiting Fulbright Researcher at the Coastal Resources Institute (CORIN), Prince of Songkla University, Hat Yai, Songkhla, 90112, Thailand.  相似文献   
60.
ABSTRACT: The paper presents a methodology for outdoor recreation analysis in a comprehensive State water resources planning study. This methodology applies to determination of recreation participation desires among the population, allocation of those desires to areas of potential resources within which they must be satisfied, comparison of the areal potential resources against the allocated desires to identify areas having recreational resource deficits or needs, and exploration of alternative solutions to the identified needs. Major elements discussed are: market area, inflow-outflow, resource desire determination and projection, resource desire allocation, facility inventory, resource desire-resource analysis and alternative solutions to identified needs of water-oriented outdoor recreation.  相似文献   
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