首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
山东海洋休闲渔业的SWOT分析与对策   总被引:2,自引:0,他引:2  
休闲渔业是一种新型的渔业经营形式,在丰富渔业内容的同时,扩大了渔业发展的空间,给渔民、渔区带来更大的经济效益和社会效益。山东省发展休闲渔业具有一定的资源和区域优势,但同样存在一些问题和潜在的威胁。本文应用SWOT方法对山东省发展海洋休闲渔业的优势、劣势进行分析,并针对其发展面临的机遇和威胁提出了相应的对策。  相似文献   

2.
Six working groups were set up at the joint IUCN/SCAR Symposium on the scientific requirements for Antarctic conservation. These were charged with (i) identifying gaps in the scientific understanding of ecosystems that inhibit rational management, and (ii) considering whether present conservation practices were taking enough account of what is known of the region, particularly with regard to protected areas. There is still a need for synthesis and further work on stocks and the life history of krill in the pelagic ecosystem. Monitoring strategies are not clear and biomass determinations are difficult and costly. Information on squid is lacking. Although there is much information on higher consumers there is a gap in knowledge of dynamic ecological processes, particularly in winter. Studies of crabeater seals deserve priority. The network of existing protected areas is inadequate for preserving all species of birds, seals and whales; new criteria are needed for effective conservation. On land, the Agreed Measures provide an adequate framework for conservation, though additional steps are needed to ensure adherence to their provisions. Selection criteria are deficient. Additional measures are required; these include the establishment of Conservation Areas, general provision for the protection of biota, and a code of conduct for all activities. Exploitation of marine mammals (except the minke whale) has ceased. Monitoring whales presents difficulties. Fish stocks are significantly exploited and better monitoring is required. Prediction of trends in krill catches is difficult but there has been a large drop in krill fishing effort. Localised effects on predators could occur with catches of a few million metric tons. Commercial mineral exploitation in the Antarctic is a long way in the future but exploitation could result from political motives. There is a need for a data base for the design of investigations and impact assessment. Operational hazards need to be modelled in advance. It is important not to go too far too fast. Antarctica is unique in its control measures and their implementation. However, Specially Protected Areas lack management plans and management plans at Sites of Special Scientific Interest are not consistent. There are inadequate guidelines on the development of scientific stations. The coastal region must be regarded as critical habitat. A comprehensive conservation strategy is required with a broader network of protected areas giving full consideration to marine as well as terrestrial areas. Copies of the full working group reports have been deposited with IUCN and SCAR.  相似文献   

3.
Harbour seals and harbour porpoises are top predator species from the North Sea, have long life spans and hence, are known to accumulate high levels of anthropogenic contaminants. To gain knowledge about the behaviour of naturally-produced compounds in these marine mammals, the biomagnification of naturally-produced methoxylated polybrominated diphenyl ethers (MeO-PBDEs) was assessed. The biomagnification of MeO-PBDEs (2′-MeO-BDE 68 and 6-MeO-BDE 47) was lower in harbour seals (all biomagnification factors (BMFs) < 1) compared to the same age–gender groups of the harbour porpoises (all BMFs > 1). This may indicate a better metabolic breakdown of MeO-PBDEs in harbour seals, as was previously suggested for polybrominated diphenyl ethers (PBDEs). In both predators, 6-MeO-BDE 47 had the highest concentrations (range: 45–483 ng/g lw and 2–38 ng/g lw for harbour porpoises and seals, respectively) compared to 2′-MeO-BDE 68 (range: 2–28 ng/g lw and 1–6 ng/g lw for harbour porpoises and seals, respectively). In general, the highest concentrations were found in juveniles, suggesting an increased biotransformation capacity with age or the influence of dilution by growth for both species. Here we show that naturally-produced brominated organic compounds can biomagnify and accumulate in North Sea top predators, although to a lesser extent than anthropogenic lipophilic contaminants, such as polychlorinated biphenyls (PCBs) or PBDEs.  相似文献   

4.
Small-scale fisheries in coral reef areas support the livelihoods of millions of people worldwide. Anthropogenic impacts such as overfishing and climate change increasingly threaten both the reef ecosystem and the livelihood security of the people that depend on the reefs. Adaptive management strategies are needed to adequately deal with these threats, but they require an understanding of the underlying drivers, which often originate and act on multiple levels. Using a social-ecological system approach, the coral reef fishery of the Spermonde Archipelago in South Sulawesi/Indonesia is assessed to identify key drivers and strategic leverage points for management. Under the influence of international markets and technological changes, several export-oriented fisheries have developed in the area that led to distinct subsequent peaks in fishing activity in a pattern of sequential marine resource exploitation. In response to stressors such as seasonality and overfishing of individual locations or species, a number of coping strategies have developed locally. These include extensive borrowing from fishing patrons, diversification of fishing methods, fishing migrations, and the crafting of local institutions to regulate fishing activity. However, the coping strategies hinder, and even decrease, the capacity of the system to adapt to future stressors and undermine the sustainability of the fishery. Potential strategies that target different levels of the fishery system in order to strengthen adaptive management are identified.  相似文献   

5.
In this paper, we review the available data for polybrominated diphenylethers (PBDEs) and other flame retardants in wildlife, with the exception of fishes from Europe and North America which are covered in more detail elsewhere. More data are available for PBDEs than for other compounds, and these show that some of these compounds have become widely distributed in the environment, being found in samples from Europe, Australia, Azerbaijan, North America and the Arctic. Most available data relate to birds and their eggs and marine mammals, but the results of two food web studies are also included. The detection of PBDEs in pelagic marine mammals which feed in deep offshore waters, including baleen whales, indicate that these compounds have found their way into deep-water, oceanic food webs as well as the coastal/shallow sea examples described in detail. In the North Sea study, the most marked increase in lipid-normalised concentrations of six BDE congeners occurred during transfer from predatory fish to marine mammals. In the St. Lawrence Estuary study, marked differences in the ratios observed between species suggested that some fish species may be able to metabolise BDE99.A number of time trend studies have also been conducted, notably in guillemot eggs from Sweden (1969-2000), beluga whales from the Canadian Arctic (1982-1997 and 1989-2001) and from the St. Lawrence Estuary (1988-1999), and ringed seals from the Canadian Arctic (1981-2000). In the temperate latitudes, from these and other studies (e.g. in dated sediment cores), PBDE concentrations began to rise earlier than in those from high latitudes, in line with data for production and use. These trends have now slowed in many cases. Declines could be expected in Europe for many congeners following the cessation of manufacture and use of the penta-mix formulation in the EU, though these are not yet apparent in environmental samples. In Arctic biota, however, the rapidly rising concentrations seen currently in Canada could be expected to continue for some time, reflecting continued production and use of the penta-mix formulation in North America (>95% of the world total) and the impact of long-range atmospheric transport.  相似文献   

6.
Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) are widely used flame retardants that enter coastal waters from multiple sources and biomagnify in marine food webs. PBDEs have been detected at relatively high concentrations in harbor seals, apex predators in the northwest Atlantic. Whereas tri- to hexa-BDEs readily biomagnified from prey fishes to seal blubber, Deca-BDE (BDE-209) did not biomagnify in blubber. To explore tissue-specific differences in the accumulation/biomagnification of BFRs, we analyzed tri- to Deca-BDES in liver of 56 harbor seals (6 adult males, 50 pups), and compared hepatic concentrations and biomagnification potential with those in blubber. HBCDs were analyzed in seal liver and blubber to enable similar comparisons. Hepatic ΣPBDE (tri- to Octa-BDE) concentrations (range 35–19,547 ng/g lipid weight, lw) were similar to blubber concentrations, while α-HBCD levels in seal liver (range 2–279 ng/g lw) were significantly higher than levels in blubber. Tissue distribution of PBDEs and α-HBCD varied significantly by age and, surprisingly, by gender among the pups. Biomagnification of α-HBCD from fish to seal liver and blubber was negligible to low, implying that harbor seals can metabolize this persistent isomer. Similar to the patterns in blubber, tri- through hexa-BDEs were highly biomagnified from fish to seal liver. In contrast, BDE-209 concentrations in liver were up to five times higher than those in blubber, which is consistent with observations that BDE-209 migrates to perfused tissues such as the liver in biota. Although detection frequency was low, BDE-209 levels in seal liver were up to ten times higher than those in their prey fish, suggesting that the accumulation/biomagnification of Deca-BDE in marine food webs is tissue-specific. As BDE-209 is the dominant PBDE found in marine sediments, its biomagnification in marine ecosystems is of concern.  相似文献   

7.
A central tenet of the nuclear industry's monitoring philosophy is that, if environmental levels of radioactivity are kept low enough to safeguard humans, then other species will also be protected. This paper reviews the background to this assumption and shows that, for species such as marine top predators, there are no supporting data. Thus, recent claims that radioecological studies on these species are unnecessary appear to be unfounded. A number of areas for future research are outlined and it is suggested that studies of marine top predators could lead to a greater understanding of the behaviour of radionuclides in the marine environment.  相似文献   

8.
Small pelagic fishes are particularly abundant in areas with high environmental variability (zones of coastal upwelling and areas of tidal mixing and river discharge), and because of this, their abundance suffers large inter-annual and inter-decadal fluctuations. In Portugal, the most important species in terms of landings are European sardine, Atlantic horse mackerel and Atlantic chub mackerel. Small pelagic fish landings account for 62.8 % of the total fish biomass and represent 32.7 % of the economical value of all catches. We have investigated trends in landings of these small pelagic fishes and detected the effects of environmental factors in this fishery. In order to explain the variability of landings of small pelagic fishes, we have used official landings (1965–2012) for trawling and purse seine fisheries and applied generalized linear models, using the North Atlantic Oscillation index (NAO) (annual and winter NAO index), sea surface temperature (SST), wind data (strength and North–South and East–West wind components) and rainfall, as explanatory variables. Regression analysis was used to describe the relationship between landings and SST. The models explained between 50.16 and 51.07 % of the variability of the LPUE, with the most important factors being winter NAO index, SST and wind strength. The LPUE of European sardine and Atlantic horse mackerel was negatively correlated with SST, and LPUE of Atlantic chub mackerel was positively correlated with SST. The use of landings of three important species of small pelagic fishes allowed the detection of variations in landings associated with changes in sea water temperature and NAO index.  相似文献   

9.
The problem of arsenic pollution of groundwater used for domestic water supplies is now well recognised in Bangladesh, India and some other countries of South and South-east Asia. However, it has recently become apparent that arsenic-polluted water used for irrigation is adding sufficient arsenic to soils and rice to pose serious threats to sustainable agricultural production in those countries and to the health and livelihoods of affected people. This paper reviews the nature of those threats, taking into account the natural sources of arsenic pollution, areas affected, factors influencing arsenic uptake by soils and plants, toxicity levels and the dietary risk to people consuming arsenic-contaminated rice.  相似文献   

10.
This paper is an attempt to synthesize and briefly examine the causes of the marine fisheries crisis, and to speculate about future initiatives. Ultimately, the human appetite is at the root of the marine fisheries crisis. But religion, technology, population pressure, science and our economic systems have provided vehicles for human appetite and thus contributed to overfishing. These various topics are further discussed in the context of the potential restoration of marine fisheries populations. All titles with gratitude to The Talking Heads. Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   

11.
Climate change can cause significant (un)foreseen changes in the fisheries sector. However, adaptation has the potential to moderate some of the impacts. This paper explores the challenges faced by both freshwater and marine fisheries sector in addressing climate change and teases out intervention measures from 21 African countries. The paper uses document analysis and draws selected analysis parameters from the grounded theory. The data are obtained from the United Nations Framework Convention on Climate Change National Communication reports. Among the key adaptation measures emerging from the analysis are: fish breeding, integrated coastal management, putting in place appropriate policies, water and flood management as well as research and development. The study concludes that adaptation in the African fisheries sector should be prioritised, an aspect that could also apply elsewhere in the world to enhance food security.  相似文献   

12.
Marine resource management programs face conflicting mandates: to scale-up marine conservation efforts to cover larger areas and meet national and international conservation targets, while simultaneously to downscale and decentralize management authority to resource users and local communities. These conflicting goals create tensions in marine resource management. This paper explores these tensions by presenting and evaluating the outcomes of a fisheries co-management program on the island of Pemba, Tanzania, where institutions and scale were configured and reconfigured under externally funded programs to improve marine conservation through co-management. The initial institutional arrangements for co-management supported a functioning system to protect marine resources, ensure fishermen’s access, and distribute tourism revenues. However, a subsequent push to scale-up marine management reconfigured institutional arrangements and power in a more hierarchical and potentially weaker system. With the expansion of the co-management program, protected area coverage, financial resources, and the number of community organizations created for fisheries co-management expanded tremendously; however, community participation in marine management decreased, and the fishermen’s association previously involved in co-management dissolved. Several factors contributed to this outcome: inadequate time to solidify co-management institutions and arrangements, diverse resource users inexperienced with local management, a sudden and substantial new source of funding, and political pressures to restructure marine management. Rather than focusing primarily on expanding coverage and devolving authority, it is important to adapt co-management arrangements to the local contexts in which they operate.  相似文献   

13.
Humanity depends on the marine environment for a range of vital ecosystem services, at global (e.g. climate regulation), regional (e.g. commercial fisheries) and local scales (e.g. coastal defence and recreation). At the same time, marine ecosystems have been exploited for centuries, and many systems today are under stress from multiple sources. Recent studies have shown how both climate change and fishing have caused long-term changes in the marine environment. However, there is still poor understanding of how these changes influence change in coastal ecosystem services. In this paper, an integrated modelling approach is used to assess how the final delivery of marine ecosystem services to coastal communities is influenced by the direct and indirect effects of changes in ecosystem processes brought about by climate and human impacts, using fisheries of the North Sea region as a case study. Partial least squares path analysis is used to explore the relationships between drivers of change, marine ecosystem processes and services (landings). A simple conceptual model with four variables—climate, fishing effort, ecosystem process and ecosystem services—is applied to the English North Sea using historic ecological, climatic and fisheries time series spanning 1924–2010 to identify the multiple pathways that might exist. As expected, direct and indirect links between fishing effort, ecosystem processes and service provision were significant. However, links between climate and ecosystem processes were weak. This paper highlights how path analysis can be used for analysing long-term temporal links between ecosystem processes and services following a simplified pathway.  相似文献   

14.
The aim of the paper was plutonium (238Pu and 239+240Pu) determination in seabirds, permanently or temporarily living in northern Poland at the Baltic Sea coast. Together 11 marine birds species were examined: 3 species permanently residing in the southern Baltic, 4 species of wintering birds and 3 species of migrating birds. The obtained results indicated plutonium is non-uniformly distributed in organs and tissues of analyzed seabirds. The highest plutonium content was found in the digestion organs and feathers, the smallest in skin and muscles. The plutonium concentration was lower in analyzed species which feed on fish and much higher in herbivorous species. The main source of plutonium in analyzed marine birds was global atmospheric fallout.  相似文献   

15.
The composition and abundance of marine biota in Israeli marine ecosystems are affected by natural and anthropogenic pressures, including blooms of non-indigenous jellyfish and overfishing. While overfishing is itself a major stressor of fish stocks, it appears that jellyfish may be outcompeting fish for scarce planktonic food resources. Beyond this direct impact on fisheries, jellyfish–ecosystem interactions are also important because of the disturbance they cause to multiple users of marine and coastal resources. This paper documents the concurrent changes in the composition of marine biotic communities, including jellyfish proliferation and dwindling stocks of endemic, commercially valuable fish and the rising rate of bottom trawling in Israeli fisheries. The capacity to deal directly with jellyfish is limited by lack of knowledge about their ecology. Therefore, we suggest that bolstering fish stocks and increasing their competitive advantage in the food web may be instrumental in limiting jellyfish blooms. Coordination of fishing and conservation policies is recommended, as are modifications to marine waste management and deployment of submerged artificial substrates.  相似文献   

16.
长江口及邻近水域渔业资源监测现状分析   总被引:1,自引:0,他引:1  
长江口及邻近水域是我国多种重要鱼类产卵、索饵、育肥的优良场所和洄游通道,对于该水域渔业资源进行有效监测是开展资源评估和养护的基础.以渔业资源监测的4种常见途径,即注册制度、问卷调查及访问调查、直接监测和报告制度为框架,对照总结了这一水域各种监测项目的发展水平和缺陷,特别针对依赖于渔业的调查和独立于渔业的调查,详细分析了渔业观察员项目、科考船、采样调查设计、渔业声学调查、标志放流、鱼卵仔稚鱼调查等环节的发展现状.在此基础上对现有监测项目的发展完善提出改进建议,旨在为该水域后续建立科学合理的渔业资源监测体系积累基础参考资料.  相似文献   

17.
Around 130 publications reporting studies on radionuclide transfer to freshwater biota species conducted in the former USSR were reviewed to provide the concentration ratio values. None of these studies were available up to now in the English language reviews or publications. The values derived have been compared with the CR values used for freshwater systems in the International reviews. For some radionuclides reviewed in this paper, the data are in good agreement with the mean CR values presented earlier, however for some of them, in particular, for 241Am (bivalve molluscs, gastropods and pelagic fish), 60Co (gastropods, benthic fish and insect larvae), 90Sr and 137Cs (benthic fish and zooplankton), the mean values given here are substantially different from those presented earlier. The data reported in this paper for thirty five radionuclides and eleven groups of freshwater species markedly improve the extent of available data for evaluation of radiation impact on freshwater species.  相似文献   

18.
The urgency of managing marine resources is based on the fact that half of the world stocks are fully exploited, excluding those stocks that are already depleted. Artisanal fisheries in Brazil, both inland and coastal, are responsible for about half of the country’s catches. Therefore, management of local artisanal fisheries is a necessity that provides an additional benefit, considering the observation that decentralization and the use of local ecological knowledge (LEK) in management have given better results than centralized, top-down management. In this study, a third system of knowledge–based on practice and training–is built from the local and scientific systems of knowledge, and a method to accomplish practical steps in local management is shown. Four elements are considered for the process of linking systems towards management: (1) an understanding of the natural environment of the fishery and on the use of natural resources by locals; (2) the knowledge of the marine area used by fishers, i.e., location of fishing spots for each species; (3) the understanding of fisher behavior, e.g., using tools from optimal foraging theory; and (4) the knowledge fishers have of the biology and ecology of species and their LEK, based on studies of the ethnobiology, ethnoecology, and ethnotaxonomy of fish. Considering the availability of publications on topics 1 and 2, illustrative cases are shown using optimal foraging models in Itaipu Beach, Rio de Janeiro and São Paulo Bagre, Cananéia, São Paulo, and using common snook, Centropomus undecimalis, as an example for a target species. Finally, local programs including training courses using both scientific and local knowledge are proposed within coastal artisanal fisheries.  相似文献   

19.
In a number of metropolitan areas of the country, failure to attain national primary air quality standards for total suspended particulates (TSP) has fostered a detailed reexamination of the nature of the urban TSP problem. Reentrained dust from paved streets and other traffic-related emissions are now recognized as major sources of TSP in urban areas. While numerous reports and studies have examined this subject, some significant aspects of urban road dust have not been studied in enough detail, if at all. Examples of this are the effects of gutters and pavement composition and shape. This paper discusses those areas of the urban road dust problem that are felt to require further attention and outlines the priorities with which the data should be obtained.  相似文献   

20.
River fisheries are extremely important for food-security among the rural poor in many tropical countries. The growing populations and rapid industrialisation of these countries require that appropriate action should be taken to sustain the resources for future generations. However, an incomplete understanding of river fisheries biology, at the managerial level, often hampers proper planning and management. This is partly due to the difficult access to large parts of such river basins, the complex nature of the fisheries, and in many cases a severe lack of research funds. In contrast, the thousands, or often millions of people who live along the shores of the rivers and rely on the fishery for their daily survival, have a very intimate knowledge of the behaviour and biology of the fish. In this situation, gathering the knowledge of the fishers may provide politicians or planners with baseline knowledge in a relatively quick and cheap way.This paper discusses two years of research using local knowledge in the study of fish migration and spawning in the Lower Mekong Basin. The study involves semi-structured interviews with 355 expert fishermen in four countries along 2,400 km of the Mekong mainstream. By piecing together information from fishermen in different areas, we were able to construct migration maps, and provide rough estimates of the spawning period for 50 fish species. We conclude that river fisheries research can benefit significantly from local knowledge as the basis for future research.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号