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71.
Sustainable provision of seafood from wild-capture fisheries and mariculture is a fundamental component of healthy marine ecosystems and a major component of the Ocean Health Index. Here we critically review the food provision model of the Ocean Health Index, and explore the implications of knowledge gaps, scale of analysis, choice of reference points, measures of sustainability, and quality of input data. Global patterns for fisheries are positively related to human development and latitude, whereas patterns for mariculture are most closely associated with economic importance of seafood. Sensitivity analyses show that scores are robust to several model assumptions, but highly sensitive to choice of reference points and, for fisheries, extent of time series available to estimate landings. We show how results for sustainable seafood may be interpreted and used, and we evaluate which modifications show the greatest potential for improvements.  相似文献   
72.
Law of the Sea negotiations and The Fishery Conservation and Management Act of 1976 create new options in fisheries management. Historical analysis of two major management programs in the United States of America, Columbia River chinook salmon (Oncorhynchus tshawytscha) and Pacific halibut (Hippoglossus stenolepis), shows two unresolved management problems. One is the innovativeness of fishermen in seeking ways to improve their harvests. The other is changing social priorities that are largely unpredictable and outside the control of fisheries managers. A method for analysis of patterning associated with management goals is illustrated. Since the general management goals are harvest improvement and more predictability, measures are used which show the adequacy of fit and reduction in variability between actual and predicted management outcomes.  相似文献   
73.
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   
74.
A simulation model was developed to describe linkages among fish food web, nutrient cycling, and contaminant processes in the southern basin of Lake Michigan. The model was used to examine possible effects of management actions and an exotic zooplankter (Bythotrephes) on Lake Michigan food web and contaminant dynamics. The model predicts that contaminant concentrations in salmonines will decrease by nearly 20% ifBythotrephes successfully establishes itself in the lake. The model suggests that this decrease will result from lowered transfer efficiencies within the food web and increased flux of contaminants to the hypolimnion. The model also indicates that phosphorus management will have little effect on contaminant concentrations in salmonines. The modeling exercise helped identify weaknesses in the data base (e.g., incomplete information on contaminant loadings and on the biomass, production, and ecological efficiencies of dominant organisms) that should be corrected in order to make reliable management decisions.  相似文献   
75.
The shellfish aquaculture industry (SAI) has operated in Baynes Sound, British Columbia (BC) since the early 1900s. Recognizing the economic potential of the area, the industry has requested additional farming opportunities. However, Baynes Sound upland residents and many other stakeholders have expressed concerns that SAI activities are having a negative impact on the environment, quality of life, and other nonaquaculture resource uses in the area. In order to address these issues, the Action Plan was initiated by a BC government interagency project team in November 2001. To assist in assessing the strategic aspects of this conflict, the decision support system GMCR II is employed here to apply a new methodology, the graph model for conflict resolution, to systematically analyze the ongoing conflict over shellfish aquaculture development in Baynes Sound within a social, economic, and environmental framework. Valuable insights are procured to guide decision-makers toward sustainability of the shellfish industry.  相似文献   
76.
In determining the importance of criteria in the management of fisheries, two key issues stand out—the definition of a succinct set of criteria and the determination of which interest groups play a defining role in the management development process. This is indeed the case for all natural resource management problems, and many other environmental problems as well. The analytic hierarchy process (AHP) provides an effective framework for such an analysis. The AHP is generally used to evaluate importance amongst criteria based on the concept of paired comparison. This paper considers the development of a representative criteria hierarchy, and uses data obtained from a pairwise comparison survey based on the UK fisheries of the English Channel to investigate priorities that exist among different interest groups in the fisheries. The implementation of the AHP in this application provides a useful tool for analysis of criteria amongst groups involved in the management process with diverse interests.  相似文献   
77.
Reliable catch information is scarce for most sharks and rays worldwide, with almost half of the stocks considered to be Data Deficient due to limited species-specific catch statistics. Western Australia (WA) hosts a diverse number of shark and ray species, some of which are considered to be threatened with extinction at a global level. Commercial catch statistics only account for shark and ray landings. The present study used the best available information to reconstruct unaccounted and unreported catches for 47 shark and ray taxa to better understand the impact of fishing. For some species, there was good agreement between reconstructed catches and reported landings, but overall reconstructed catches were 57% higher than those derived from official statistics alone, underestimating the actual extraction level for many species. The reconstructed catch time series provide the basis for the assessment of all species of sharks and rays captured in WA, including protected species that interact with commercial and recreational fisheries.Supplementary informationThe online version of this article (10.1007/s13280-020-01495-6) contains supplementary material, which is available to authorised users.  相似文献   
78.
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   
79.
The fisheries of Lake Victoria have undergone a major transformation over the last three decades. The character of the lake has been subject to the influence of many powerful factors including: substantial increases in fishing effort; growing integration into the global fish market; acceleration of anthropogenic activities in the catchment area; demographic change; the influence of adverse shifts in the climate; and introduction of exotic plant and animal species. The task of managing the lake's resources, therefore, has never been more daunting. This article argues that, in most cases, the authorities charged with achieving the goal of sustainable development for the fishery, have failed to address the symptoms—let alone the origins—of the current unsustainable tendencies embedded in the social, economic and political fabric of Lake Victoria's riparian States. It is these factors that directly impinge upon the success of management initiatives for the lake. The article argues that if sustainable development is to be achieved, then stakeholders must act in concert, eliminate unsustainable practices and reprogramme development plans to focus on realistic goals. A possible way forward will be to develop a participatory management system.  相似文献   
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