24,236 research outputs found

    Diagnosis and the management constituency of small-scale fisheries

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    Diagnosis and adaptive management can help improve the ability of small-scale fisheries (SSF) in the developing world to better cope with and adapt to both external drivers and internal sources of uncertainty. This paper presents a framework for diagnosis and adaptive management and discusses ways of implementing the first two phases of learning: diagnosis and mobilising an appropriate management constituency. The discussion addresses key issues and suggests suitable approaches and tools as well as numerous sources of further information. Diagnosis of a SSF defines the system to be managed, outlines the scope of the management problem in terms of threats and opportunities, and aims to construct realistic and desired future projections for the fishery. These steps can clarify objectives and lead to development of indicators necessary for adaptive management. Before management, however, it is important to mobilize a management constituency to enact change. Ways of identifying stakeholders and understanding both enabling and obstructive interactions and management structures are outlined. These preliminary learning phases for adaptive SSF management are expected to work best if legitimised by collaborative discussion among fishery stakeholders drawing on multiple knowledge systems and participatory approaches to assessment. (PDF contains 33 pages

    Approaches and frameworks for management and research in small-scale fisheries in the developing world

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    Commonly adopted approaches to managing small-scale fisheries (SSFs) in developing countries do not ensure sustainability. Progress is impeded by a gap between innovative SSF research and slower-moving SSF management. The paper aims to bridge the gap by showing that the three primary bases of SSF management--ecosystem, stakeholders’ rights and resilience--are mutually consistent and complementary. It nominates the ecosystem approach as an appropriate starting point because it is established in national and international law and policy. Within this approach, the emerging resilience perspective and associated concepts of adaptive management and institutional learning can move management beyond traditional control and resource-use optimization, which largely ignore the different expectations of stakeholders; the complexity of ecosystem dynamics; and how ecological, social, political and economic subsystems are linked. Integrating a rights-based perspective helps balance the ecological bias of ecosystem-based and resilience approaches. The paper introduces three management implementation frameworks that can lend structure and order to research and management regardless of the management approach chosen. Finally, it outlines possible research approaches to overcome the heretofore limited capacity of fishery research to integrate across ecological, social and economic dimensions and so better serve the management objective of avoiding fishery failure by nurturing and preserving the ecological, social and institutional attributes that enable it to renew and reorganize itself. (PDF contains 29 pages

    Approaches and frameworks for management and research in small-scale fisheries in the developing world

    Get PDF
    Commonly adopted approaches to managing small-scale fisheries (SSFs) in developing countries do not ensure sustainability. Progress is impeded by a gap between innovative SSF research and slower-moving SSF management. The paper aims to bridge the gap by showing that the three primary bases of SSF management--ecosystem, stakeholdersÆ rights and resilience--are mutually consistent and complementary. It nominates the ecosystem approach as an appropriate starting point because it is established in national and international law and policy. Within this approach, the emerging resilience perspective and associated concepts of adaptive management and institutional learning can move management beyond traditional control and resource-use optimization, which largely ignore the different expectations of stakeholders; the complexity of ecosystem dynamics; and how ecological, social, political and economic subsystems are linked. Integrating a rights-based perspective helps balance the ecological bias of ecosystem-based and resilience approaches. The paper introduces three management implementation frameworks that can lend structure and order to research and management regardless of the management approach chosen. Finally, it outlines possible research approaches to overcome the heretofore limited capacity of fishery research to integrate across ecological, social and economic dimensions and so better serve the management objective of avoiding fishery failure by nurturing and preserving the ecological, social and institutional attributes that enable it to renew and reorganize itself.Developing countries, Fishery management, Artisanal fishing, Research

    Wave impedance matrices for cylindrically anisotropic radially inhomogeneous elastic solids

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    Impedance matrices are obtained for radially inhomogeneous structures using the Stroh-like system of six first order differential equations for the time harmonic displacement-traction 6-vector. Particular attention is paid to the newly identified solid-cylinder impedance matrix Z(r){\mathbf Z} (r) appropriate to cylinders with material at r=0r=0, and its limiting value at that point, the solid-cylinder impedance matrix Z0{\mathbf Z}_0. We show that Z0{\mathbf Z}_0 is a fundamental material property depending only on the elastic moduli and the azimuthal order nn, that Z(r){\mathbf Z} (r) is Hermitian and Z0{\mathbf Z}_0 is negative semi-definite. Explicit solutions for Z0{\mathbf Z}_0 are presented for monoclinic and higher material symmetry, and the special cases of n=0n=0 and 1 are treated in detail. Two methods are proposed for finding Z(r){\mathbf Z} (r), one based on the Frobenius series solution and the other using a differential Riccati equation with Z0{\mathbf Z}_0 as initial value. %in a consistent manner as the solution of an algebraic Riccati equation. The radiation impedance matrix is defined and shown to be non-Hermitian. These impedance matrices enable concise and efficient formulations of dispersion equations for wave guides, and solutions of scattering and related wave problems in cylinders.Comment: 39 pages, 2 figure

    REDUCING SEASONALITY IN DAIRY PRODUCTION

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    Livestock Production/Industries,

    Practices Used by Dairy Farmers to Reduce Seasonal Production Variability

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    The objective of this analysis was to identify the production practices used by farmers to change seasonal production. Production practices included milk production per cow, proportion of cows milking, number of first lactation animals entering the herd, number of cows leaving the herd, number of days to first breeding, and calves born. Farms that participated in a seasonal pricing plan during 1993, 1994, and 1995 decreased production practice seasonality in response to price premiums, which caused a decrease in production seasonality compared to nonparticipating farms. Participating farms showed a preference for adjusting entering first lactation animals and number of calves born, but did make adjustments in other practices as well.Livestock Production/Industries,

    Two Distinct, Geographically Overlapping Lineages of the Corallimorpharian Ricordea Florida (Cnidaria: Hexacorallia: Ricordeidae)

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    We examined the genetic variation of the corallimorpharian Ricordea florida; it is distributed throughout the Caribbean region and is heavily harvested for the marine aquarium trade. Eighty-four distinct individuals of R. florida were sequenced from four geographically distant Caribbean locations (Curaçao, Florida, Guadeloupe, and Puerto Rico). Analysis of the ribosomal nuclear region (ITS1, 5.8S, ITS2) uncovered two geographically partially overlapping genetic lineages in R. florida, probably representing two cryptic species. Lineage 1 was found in Florida and Puerto Rico, and Lineage 2 was found in Florida, Puerto Rico, Guadeloupe, and Curaçao. Because of the multi-allelic nature of the ITS region, four individuals from Lineage 1 and six from Lineage 2 were cloned to evaluate the levels of hidden intra-individual variability. Pairwise genetic comparisons indicated that the levels of intra-individual and intra-lineage variability (\u3c1%) were approximately an order of magnitude lower than the divergence (~9%) observed between the two lineages. The fishery regulations of the aquarium trade regard R. florida as one species. More refined regulations should take into account the presence of two genetic lineages, and they should be managed separately in order to preserve the long-term evolutionary potential of this corallimorpharian. The discovery of two distinct lineages in R. florida illustrates the importance of evaluating genetic variability in harvested species prior to the implementation of management policies
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