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1.
Worldwide there is a declining trend in natural fish catch (FAO, The state of world fisheries and aquaculture. , 2002) and Bangladesh is no exception. The vast inland fisheries of Bangladesh have been declining over the years, largely a result of human alteration of the aquatic habitats arising from human interventions in the floodplain systems such as the establishment of water control structures which favor agricultural production but reduce fish habitats. It can be assumed that conventional management measures are not adequate to conserve natural fisheries and exploring alternative knowledge systems to complement existing management is warranted. This paper focuses on local ecological knowledge and several other local practices held by fishers engaging directly with floodplain ecosystems. These knowledge systems and practices may be valuable tools for understanding ecosystems processes and related changes and developing local level responses to avert negative consequences of such changes. This may help in devising alternatives to ecosystem management and the conservation of floodplain fish habitats of Bangladesh and elsewhere in the world. This study was conducted in a natural depression (locally called beel) and its surrounding floodplain system located in north central Bangladesh which has become highly degraded. The results of the study indicate that the fishers and local users of the floodplain ecosystems are rich in local ecological knowledge concerning the hydrology of the floodplains and small lakes, the habitat preferences of fish, the role of agricultural crops on fish habitats, and the impact of habitat human interventions in aquatic ecosystems. Given the apparent inadequacy of the present management regime, this article argues for an inclusion of local knowledge and practices into habitat management as a more holistic approach to floodplain habitat restoration and conservation that encourages multi-level cooperation and which builds on diversified knowledge systems.  相似文献   

2.
Disproportionately little attention has been paid to the dry season trade‐off between rice and (inland capture) fish production on the floodplains of Bangladesh, compared to the same trade‐off during the flood season. As the rural economy grows increasingly dominated by dry‐season irrigated rice production, and floodplain land and water come under ever‐increasing pressure during the dry winter months, there is an urgent need to focus attention on these dry months that are so critical to the survival and propagation of the floodplain resident fish, and to the poor people that depend on these fish for their livelihood. This article examines three important dry‐season natural resource constraints to floodplain livelihoods in Bangladesh, and finds a common factor at the heart of all three: rice cultivation on lands at low and very low elevations. The article articulates the system interlinkages that bind these constraints and the long‐run trend towards irrigated rice cropping on lower‐lying lands, and suggests a management approach based on locally tailored strategies to arrest this trend. Apart from its direct relevance to the floodplains of Bangladesh, which support more than 100 million people, these lessons have relevance for river floodplain systems elsewhere in the developing world, notably the Mekong Delta.  相似文献   

3.
Inland (floodplain) fisheries remain the most important contributor to fish production in Bangladesh. They have in the past been administered to generate government revenue without due concern for sustainability or equity. Community Based Fisheries Management (CBFM) is a possible solution and was tested in 19 waterbodies (rivers and beels) during 1996-2000. The outcomes so far are assessed with respect to social, institutional, and physical context, and the interactions that arose in establishing CBFM. The lessons drawn are that: it was essential that communities obtained rights over the fisheries, strong facilitation was necessary, taking up visible resource management actions greatly helped, success was more likely in homogeneous communities, external threats were a strong limiting factor, clear boundaries and small fisheries were not so critical, and new institutions could be built with as much ease (or difficulty) as modifying existing ones. Effective well-defined partnerships of NGOs and government were not easy to establish but were sufficiently beneficial that in several locations new community institutions for fisheries management were established. This is a slow process, the sustainability of local management institutions is not yet established, although they continued during an interim period without funding, further phased support is planned to strengthen these organizations and to generate evidence of impacts and momentum to influence wider fisheries policy in and beyond Bangladesh.  相似文献   

4.
The choice of flood control techniques in Bangladesh is reviewed in the context of a case study on the impact of a small-scale polder, the Dhaka-Narayanganj-Demra (DND) Project. The results of a questionnaire survey among the urban floodplain residents, who have settled inside the polder and a control population from outside the polder, indicate that the project has achieved significant flood alleviation but has also induced considerable environmental degradation due to stagnation of water within the enclosed embankment. The project also experienced numerous problems of structural instability of embankments during major flood events. An attempt is made to extrapolate some of these adverse environmental impacts of the polder to the compartmentalization scheme, which has been proposed by a UNDP-sponsored Flood Policy Study as an innovative technique for floodplain management in Bangladesh. The findings of the study, however, do not provide an adequate basis for assessing viability of the proposed compartmentalization scheme. Nonetheless, the study illustrates the usefulness of questionnaire surveys among floodplain residents for obtaining data for project evaluation.  相似文献   

5.
《Local Environment》2008,13(1):43-54
The local private sector currently plays an important role in the protection of biodiversity of the Tonle Sap Lake. Large parts of the lake and surrounding floodplain—so-called fishing lots—are auctioned for private exploitation of the rich fisheries. The owners of fishing lots go to great lengths to ensure that there is a maximum amount of fish inside the lot by protecting the area from disturbance and poaching. The core areas of the Tonle Sap Biosphere Reserve are situated inside such fishing lots. Although it is unintended, the fishing lots and the protective measures taken by their owners to maximize extraction of fish provide effective protection for the large colonies of water birds nesting inside the core areas on the floodplain and possibly for other elements of biodiversity. Plans to end the fishing lots system in the core areas and to replace it by more effective, public-sector management and protection are prepared. Will they be counterproductive and put the core areas and their biodiversity further at risk?  相似文献   

6.
7.
Small-scale fisheries are important in Laos, where rural people heavily depend upon Mekong River and tributary fish stocks for their livelihoods. Increasing pressures from human exploitation and habitat disturbance, however, have raised serious concerns about the potential depletion of various species. This has led to the establishment of large numbers of Fish Conservation Zones (FCZs) or “no-take” fish sanctuaries in southern Laos based on a “community-based fisheries co-management” framework. This study uses the local ecological knowledge (LEK) of fishers to assess the effectiveness of village-managed FCZs in enhancing fish stocks in the mainstream Mekong River in Khong District, Champasak Province. Focus group interviews about species that are believed to have benefited from different FCZs are compared with parameters such as FCZ area, age, depth, localized gradient, water velocity, and the presence of wetland forests nearby. The results suggest that no one aspect is likely to account for variations in fish stocks; rather, it is the interaction between numerous factors that has the largest impact. Secondly, the results indicate that microhabitat diversity and protection are critical for maintaining and enhancing Mekong fisheries. Deep-water pools are particularly important as dry season refuges for many fish species, and FCZ depth may be the single most important environmental factor affecting the success of FCZs in the Mekong River. FCZs have the most potential to benefit relatively sedentary species, but may also benefit highly migratory species, given the right conditions. This study shows that integrated approaches to stock assessment that employ LEK and scientific fisheries management have considerable potential for improving Mekong capture-fisheries management.  相似文献   

8.
Despite advances in short-range flood forecasting and information dissemination systems in Bangladesh, the present system is less than satisfactory. This is because of short lead-time products, outdated dissemination networks, and lack of direct feedback from the end-user. One viable solution is to produce long-lead seasonal forecasts—the demand for which is significantly increasing in Bangladesh—and disseminate these products through the appropriate channels. As observed in other regions, the success of seasonal forecasts, in contrast to short-term forecast, depends on consensus among the participating institutions. The Flood Forecasting and Warning Response System (henceforth, FFWRS) has been found to be an important component in a comprehensive and participatory approach to seasonal flood management. A general consensus in producing seasonal forecasts can thus be achieved by enhancing the existing FFWRS. Therefore, the primary objective of this paper is to revisit and modify the framework of an ideal warning response system for issuance of consensus seasonal flood forecasts in Bangladesh. The five-stage FFWRS—i) Flood forecasting, ii) Forecast interpretation and message formulation, iii) Warning preparation and dissemination, iv) Responses, and v) Review and analysis—has been modified. To apply the concept of consensus forecast, a framework similar to that of the Southern African Regional Climate Outlook Forum (SARCOF) has been discussed. Finally, the need for a climate Outlook Fora has been emphasized for a comprehensive and participatory approach to seasonal flood hazard management in Bangladesh.  相似文献   

9.
ABSTRACT

High seas fisheries remain one of the least transparent global production practices. Distance from shore, coupled with the highly mobile nature of fish stocks, has put attention on new monitoring, control and surveillance technologies to collect spatially referenced data on the location of fishing vessels, gears and even fish stocks and eradicate illegal, unreported and unregulated fishing activity. Faced with their nascent implementation, research is yet to address how these technologies are reconfiguring the roles and responsibilities of public and private actors involved in fisheries management, including who collects and controls fisheries related information. In this paper, we compare three monitoring, control and surveillance technologies that are gaining traction in fisheries; the use of private fish attraction devices in oceanic tuna fisheries, unmanned public drones for marine surveillance and global satellite monitoring of fishing vessels. In doing so, we question how different configurations of actors are structuring flows of information and with what effect on sustainability performance of high seas fisheries. We also explore how these technologies configure new (and imagined) geographies of high seas fisheries which challenge existing modes of fisheries management.  相似文献   

10.
/ Bangladesh has recently tested a program called the Flood Action Plan (FAP) to solve its chronic flood problem. The FAP envisages that all the major rivers of Bangladesh will eventually be embanked on both sides in order to prevent flooding. This paper reports on the responses of rural women to the possible impacts of the proposed embankment projects as outlined in the FAP. A further attempt is also made to compare their responses with the results of an earlier survey conducted among male respondents. Data for this study were collected from two rural areas of Bangladesh. It shows that almost all respondents had heard about the proposed construction and that they overwhelmingly support the embankment project of the FAP. Respondents are also aware of both positive and negative impacts of embankment construction. Similar findings were also reported by a previous study dealing with male responses to the embankment project. KEY WORDS: Flood Action Plan; Bangladesh; Women  相似文献   

11.
We applied the adaptive management approach to analyze the demand and feasibility of adaptive management of fish stocks in a large regulated lake, Oulujärvi, in northern Finland. The process consisted of four phases: (1) analysis of the current state of the fisheries system (fishers, related markets and industry, fisheries researches and authorities, related organizations, etc.); (2) analysis of the objectives of different stakeholders; (3) the composition of alternative management strategies and assessment of their impacts; and (4) recommendations for future management. We used catch statistics from the period 1973–1995 to analyze fish stocks and fishing. Fish species involved were brown trout (Salmo trutta L.), whitefish [Coregonus lavaretus (L.) sl.], vendace (Coregonus albula L.); and pikeperch (Stizostedion lucioperca L.). Questionnaires and interviews were applied to ascertain the opinions of different groups of fishermen. Several models and cost–benefit analysis were used to assess the ecological, economic, and social impacts of three alternative management strategies. The results emphasize that when determining stocking levels and fishing regulations, the system should be considered as a whole, and impacts on major fish species and different groups of fishermen should be assessed. The stocking policy and fishing regulations should also be flexible to accommodate changing biotic and societal conditions. The key questions in applying the adaptive management process in Oulujärvi fisheries are how to determine clear objectives for fisheries management, find a fisheries management structure that provides workable interactions between different stakeholders, and arrange cost-effective monitoring. The lessons learned from the Oulujärvi experience and recommendations for fisheries management are relevant to other lakes with conflicting objectives of different stakeholders.  相似文献   

12.
This report is about a newly developed procedure for setting priorities in gully control. It explains basic gully systems and developments as influenced by geomorphologic processes on which the proposed procedure is based. These processes consist of two types: one, representing interactions between the individual gullies of a network; the other, mechanisms initiated within a given gully by localized instability conditions. Classifying gullies into continuous and discontinuous types not only allows determination of network types but also points to critical locations that must be considered by the designer.The procedure for analyzing gully networks to establish treatment priorities consists of five steps as follows: 1) determining type of network based on gully types; 2) stream ordering of the network gullies; 3) tallying tributaries of each gully; 4) analyzing stage of development of each gully; 5) ranking of treatment priorities.Situations may exist—remote location and negligent downstream effects—where gully control is not desirable and the land manager decides to let nature take its course and to await the establishment of a new stream equilibrium condition before the watershed resources will be intensively utilized. Also political or funding aspects may not permit gully control efforts. Such aspects as well as types of individual treatment measures are beyond the scope of this report. The proposed technique establishes priorities that depend on opportunities to exert greatest control for least cost and to prevent the greatest amount of future erosion.  相似文献   

13.
ABSTRACT: The rehabilitation of urban stream channels and riparian areas involves a potentially large number of design alternatives. When substantial modifications are planned, water surface profile models (e.g., HEC-2) provide a means for a thorough and efficient evaluation of many design variations. The rehabilitation of a reach of Paradise Creek, Idaho, utilized the REC-2 model to verify the appropriateness of a new channel geometry and explore the consequences of variable floodplain geometries and excavation depths. The desirability of habitat diversity, coupled with the constraints of minimized earthwork costs and adequate flow capacity, framed the floodplain design question. The final design geometry was iteratively approached using the HEC-2 model to mimic the existing channel capacity. This modeling framework produces as output computed water surface elevations for the design channel and floodplain under any discharge. Hence, the method provides the means for demonstrating that rehabilitation designs will (or will not) cause increases in flood elevations, an assessment that is generally required for project approval.  相似文献   

14.
A field investigation conducted on Boulder Creek in Boulder, Colorado evaluated impacts of flood control maintenance activities on flood conveyance, water quality, and fish habitat. Thirty-nine transects were monitored at one control site and two maintenance sites over a period of eight months. Each site was visited on more than 50 occasions in order to characterize pre- and post-maintenance conditions, and to monitor maintenance activities. Measurements along the transects included substrate composition, flow depth, velocity, and elevation. Reach-average values were assigned to variables such as in-stream vegetation, streambank stability, and woody vegetation before and after maintenance. Water temperature, dissolved oxygen, pH, specific conductance, and turbidity were sampled, and habitat suitability indices were developed pre- and post-maintenance for seven indicator fish species. Water quality impacts during maintenance consisted of high turbidity levels (> 400 NTU), which returned to background levels (0.1–15 NTU) overnight, as well as changes in mean temperature and pH. Alteration of physical channel characteristics as a result of maintenance had limited effects on habitat quality for four of seven fish species, but caused improvements in habitat quality for three fish species. The main implications of this study for floodplain management are that: (1) Flood control maintenance practices can be in direct conflict with water quality and fish habitat objectives, and should be carefully designed and implemented by an interdisciplinary team. (2) Physical habitat for some fish species can be improved as well as reduced by maintenance activities. Habitat suitability curves may be useful tools for evaluating limiting factors of the habitat and for identifying opportunities for habitat improvements as part of maintenance.  相似文献   

15.
Platanista gangetica ) are threatened in Bangladesh from the effects of dams, large embankment schemes, dredging, fisheries bycatch, directed hunting, and water pollution. Visual surveys of the section of the Jamuna River located between the divergence of the Old Brahmaputra River and the confluence of the Padma River and the section of the Kushiyara River located between the Bangladesh–India border and the confluence of the Korangi River recorded a sighting rate of 0.13 sightings/km (mean group size = 1.8 dolphins) and 0.08 sightings/km (mean group size = 3.8 dolphins), respectively. These sections of river were considered to be priority areas for investigation because several water development projects have already been constructed and more are planned for the areas. During the surveys we examined the remains of dolphins caught accidentally in plastic gillnets and observed fishermen catching the fish species Clupisoma garua using dolphin oil and body parts as a fish attractor. Additional studies are needed to assess the status of dolphins and effects of water development and fisheries bycatch. Feasibility studies should be conducted on designating dolphin/fish sanctuaries and creating artificial habitat or enhancing existing habitat in eddy countercurrent scour pools to mitigate deleterious impacts. The environmental requirements of river dolphins reflect the needs of productive and biotically diverse tropical rivers.  相似文献   

16.
This article shows how social capital impacts fisheries management at the local level in Chilika Lake, located in the state of Orissa in India. In Chilika, the different fishing groups established norms and “rules of the game” including, but not limited to, spatial limits that determine who can fish and in what areas, temporal restrictions about when and for how long people may fish, gear constraints about what harvesting gear may be used by each group, and physical controls on size and other characteristics of fish that may be harvested. A survey of the members of fishing groups has shown that the bonding social capital is strong within the Chilika fishing groups. Bonding and bridging social capital keeps the fishers together in times of resource scarcity, checks violations of community rules and sanctions, and strengthens the community fisheries management. In contrast, linking social capital in Chilika appears to be weak, as is evident from the lack of trust in external agencies, seeking the help of formal institutions for legal support, and increasing conflicts. Trust and cooperation among fishers is crucial in helping to build the social capital. A social capital perspective on fisheries governance suggests that there should be a rethinking of priorities and funding mechanisms, from “top-down” fisheries management towards “co-management” with a focus on engendering rights and responsibilities for fishers and their communities.  相似文献   

17.
This study reports the probability of increased mortality of people within the political border of Bangladesh due to the emission of fine particulate matter with diameters of 2.5 microns or less (PM2.5) from the Matarbari coal power plant (MCPP). A Gaussian plume dispersion model has been used for this estimation. The PM2.5 emission rate data are unavailable as the construction of MCPP is still in its initial stage; therefore, the anticipated PM2.5 emission rate has been estimated based on data from a number of coal‐fired power plants in India and China. To make this study more meaningful, two different emission rates have been considered representing the best‐case and worst‐case scenarios. In both cases, the intake fraction has been found to be 0.12×10?2, and the value of relative risk varies between 1.134 and 1.374, respectively. Finally, it is estimated that approximately 11.5 million people inside Bangladesh will be exposed to the PM2.5 emission from MCPP, and between 7,667 and 17,675 people will experience premature death every year.  相似文献   

18.
Research from the United Nations Food and Agriculture Organization and fishery scientists indicates that the wild catch of fish and other marine life from the oceans will not be able to increase significantly in the future, except through rehabilitation and better management of stocks. Despite the limited potential for bigger catches, fishing fleets have expanded rapidly in recent decades under government subsidies. Fishers now have approximately twice the capacity necessary to make the annual catch from the oceans. The juxtaposition of natural limits and overinvestment has created a crisis situation for the world's fishers, fishing communities, and traditional fishing cultures. Part I of this article (Natural Resources Forum, November 1994) discussed policy responses at the national and international level. How policy makers respond to the overextension of the marine fishing industry will determine the extent of job loss, hunger and dislocation that will result. Part II examines the social aspects of the world's fishing industry, including the demography of fishers, utilization of fisheries products, the relative social contribution of aquaculture and policy responses to overcapacity. Policy makers could enhance the social benefits of marine fisheries – both jobs and food – through a combination of government oversight and community-based management .  相似文献   

19.
Summary The extent of surface water acidification in Northern Europe and in Britain is reviewed and information is given on the degree to which changes in water quality appear to have influenced fish populations. The relationship between water quality and fish has been clarified by laboratory exposures, demonstrating that levels of calcium and aluminium, as well as acidity, are important for fish. It is not easy, however, to transpose laboratory findings to the field. Other determinants of a fishery should not be ignored — they include morphological and physical characteristics of lakes and streams, and biological characteristics such as food supply and species interactions.The recovery or restoration of fisheries in acid waters is crucially dependent on replacement of calcium and reduction of aluminium to bring the water quality into a range suitable for fish. While reduction of sulphur emissions, or of the atmospheric deposition of all acid generating materials, may be expected to have some effect on lake sulphate concentrations, the degree to which acidity might be realistically reduced is quite uncertain.Dr. G. D. Howells was, until recently, Head of Biology at the Central Electricity Research Laboratories of the United Kingdom's Central Electricity Generating Board (CEGB). Her previous experience includes her first degree, obtained in New Zealand, a subsequent research degree from the University of Cambridge, and three years at the University of New York studying the effects of power station siting on the Hudson River. She has a wide experience of studying pollution problems. This paper was presented at the Institution of Environmental Sciences Conference,An Update on Acid Rain, November 1984, and is published by permission of the Central Electricity Generating Board.  相似文献   

20.
Tropical fisheries, which are considered multi-species, may show selectiveness. We analyzed the degree of selectivity of fish catches in 46 sites along the Amazon basin through the percentage of biomass corresponding to the most caught fish species. Amazonian fisheries were considered moderately selective, as 54% of the sites directed more than a quarter of fishing effort to one fish species and in 87% of the sites more than half the fishing effort was directed to five fish species. Commercial fisheries were more selective than subsistence fisheries. Eleven fish species (nine of them migratory) have received more fishing pressure in the studied Amazonian regions and the catch composition differed among regions. We thus recommend that fisheries management in the Amazon basin should distribute fishing effort among more fish species; incorporate the particularities of commercial and subsistence fisheries; evaluate fishing effects on ecosystem services; and consider the biological characteristics of preferred fish.  相似文献   

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