47 research outputs found

    FISHRENT; Bio-economic simulation and optimisation model

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    Key findings: The FISHRENT model is a major step forward in bio-economic model-ling, combining features that have not been fully integrated in earlier models: 1- Incorporation of any number of species (or stock) and/or fleets 2- Integration of simulation and optimisation over a period of 25 years 3- Integration of effort and TAC-driven management policies 4- Three independent relations for stock growth, production and investments. The feedbacks within the model allow for a dynamic simulation. The main application of the model is scenario analysis of policy options. Complementary findings: The model formulates a complete set of mathematical relations, but it also con-tains a number of important assumptions, which remain to be tested empirically. Therefore the model presents a challenging agenda for empirical research, which should lead to further qualitative and quantitative improvements of the in-dividual mathematical equations and parameter values. Method: This model was developed during the EU-funded project 'Remuneration of spawning stock biomass'. Its aim was to generate consistent sets of scenarios for an assessment of potential resource rents in different EU fisheries. The model comprises six modules, each focussing on a different aspect of the functioning of the fisheries system: biology (stocks), economy (costs, earnings and profits), policy (TACs, effort and access fees), behaviour (investments), prices (fish and fuel) and an interface linking the modules together. Input, calculation and output are clearly separated. The model produces a standard set of graphics, which provide a quick insight into the results of any model run. All output of the model runs can be exported to database software for further analysis. The model has been built in Excel, which makes it accessible for most us-ers. It has been used in new applications and even translated to other software. The model is continually further developed

    Robust combination of the Morris and Sobol methods in complex multidimensional models

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    Conducting global sensitivity analysis using variance decomposition methods in complex simulation models with many input factors is usually unaffordable. An alternative is to first apply a screening method to reduce the number of input factors and then apply a variance decomposition method to the reduced model. However, usually selection of input factors is not done robustly and convergence of the screening method is not ensured. We propose two new criteria, a criterion that mimics the visual selection of the input factors and a convergence criterion. In the application of the criteria to a complex model, the Morris screening method has needed 200 trajectories to converge and the visual criterion has outperformed other existing criteria. Our proposal ensures a robust combination of the Morris and the Sobol methods that provides an objective and automatic method to select the most important input factors with a feasible computing load to achieve convergence.Basque Government IT1294-19 MTM2016-74931-

    Bioeconomic multistock reference points as a tool for overcoming the drawbacks of the landing obligation

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    The landing obligation policy was one of the major innovations introduced in the last Common Fisheries Policy reform in Europe. It is foreseen that the policy will affect the use of fishing opportunities and hence the economic performance of the fleets. The problem with fishing opportunities could be solved if single-stock total allowable catches (TACs) could be achieved simultaneously for all the stocks. In this study, we evaluate the economic impact of the landing obligation policy on the Spanish demersal fleet operating in the Iberian Sea region. To generate TAC advice, we used two sets of maximum sustainable yield (MSY) reference points, the single-stock MSY reference points defined by ICES and a set of multistock reference points calculated simultaneously using a bioeconomic optimization model. We found that the impact of the landing obligation is time and fleet dependent and highly influenced by assumptions about fleet dynamics. At fishery level, multistock reference points mitigate the decrease in the net present value generated by the implementation of the landing obligation. However at fleet level, the effect depends on the fleet itself and the period. To ensure the optimum use of fishing opportunities, the landing obligation should be accompanied by a management system that guarantees consistency between single-stock TACs. In this regard, multistock reference points represent an improvement over those currently in use. However, further investigation is necessary to enhance performance both at fleet level and in the long term.Versión del edito

    Research for PECH Committee - Discard ban, landing obligation and MSY in the Western Mediterranean Sea - the Spanish case

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    The demersal fisheries in the Mediterranean Sea are heavily overfished but the landing obligation will not help to reach MSY because it will not decrease fishing mortality. The new proposal of the Commission introduces total allowable effort as a new way to regulate Western Mediterranean demersal fisheries by significantly reducing fishing time. However, this new management measure must be complemented with increased gear selectivity, implementation of closed areas and local co-management plans. Different approaches to reduce fishing mortality may have different socio-economic impact

    Scientific, Technical and Economic Committee for Fisheries. Evaluation of fishing effort regimes - Deep sea and Western waters (STECF-11-12)

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    EWG-11-11 meeting was held on 26 – 30 September 2011 in Cadiz (Spain). This Section of the report covers the Deep Sea and Western Waters and provides fleet specific trends in catch (including discards), nominal effort and catch (landings) per unit of effort in order to advise on fleet specific impacts on stocks under multiannual management plans. STECF reviewed the report during its November 2011 plenary meeting

    Inclusion of ecological, economic, social, and institutional considerations when setting targets and limits for multispecies fisheries

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    Targets and limits for long-term management are used in fisheries advice to operationalize the way management reflects societal priorities on ecological, economic, social and institutional aspects. This study reflects on the available published literature as well as new research presented at the international ICES/Myfish symposium on targets and limits for long term fisheries management. We examine the inclusion of ecological, economic, social and institutional objectives in fisheries management, with the aim of progressing towards including all four objectives when setting management targets or limits, or both, for multispecies fisheries. The topics covered include ecological, economic, social and governance objectives in fisheries management, consistent approaches to management, uncertainty and variability, and fisheries governance. We end by identifying ten ways to more effectively include multiple objectives in setting targets and limits in ecosystem based fisheries management

    Creación de un Índice de Dependencia: Aplicación al Sector Pesquero de la CAPV

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    El artículo presenta un análisis del sector pesquero de la CAPV en su conjunto, utilizando técnicas multivariantes con el fin de obtener tanto un índice del tamaño del sector pesquero como un índice de dependencia, de los municipios pesqueros de la CAPV. Sobre estos índices se establecen grupos utilizando un análisis por conglomerados. De esta forma los municipios quedan ordenados y clasificados en términos de dependencia.Análisis multivariante, dependencia, sector pesquero
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