Fishing Technology and Optimal Distribution of Harvest Rates

In this paper we analyze the optimal management of a joint ownership fishery exploitation model where agents use different fishing gears. As opposed to other works, we consider a model in which the fishing technology affects resource's growth not only through the harvest function, but also through the natural growth rate of the resource. The main objective is to capture the evidence that some fishing gears alter the habitat of the resource, and may alter the natural growth rate of the resource. The main result we obtain is that, when the natural growth of the resource is altered by the fishing technology, the optimal stock is not independent of how harvest quotas are distributed among the agents. Thus, in this context, a fishing policy that determines, first, the optimum stock and, secondly, decides on how to distribute the harvest among the different agents will not be efficient.fisheries regulation, fishing gear's selectivity, sharing of quotas

Fishing Technology and Optimal Distribution of Harvest Rates

In this paper we analyze the optimal management of a joint ownership fishery exploitation model where agents use different fishing gears. As opposed to other works, we consider a model in which the fishing technology affects resource's growth not only through the harvest function, but also through the natural growth rate of the resource. The main objective is to capture the evidence that some fishing gears alter the habitat of the resource, and may alter the natural growth rate of the resource. The main result we obtain is that, when the natural growth of the resource is altered by the fishing technology, the optimal stock is not independent of how harvest quotas are distributed among the agents. Thus, in this context, a fishing policy that determines, first, the optimum stock and, secondly, decides on how to distribute the harvest among the different agents will not be efficient.Financial support from grants UPV/EHU 035-321-HB070/96, GV HU-1998-133 and Gobierno Vasco PI95/13 is gratefully acknowleged

Evaluación bioeconómica del cambio en la selectividad de un arte de pesca: el caso de una flota mono-específica afectada por la obligación de desembarque

The European Union Common Fisheries Policy has established a discard ban, which states that fish below a reference size cannot be sold directly for human consumption. In a fishing effort-regulated fishery, the discard ban can result in extra handling, storing and landing costs. In an output-regulated fishery, this policy might also limit the effort levels as all the catches count against the quota. In both cases, this regulation can reduce the economic performance of the companies, even in single-species fisheries. A possible solution is to increase the mesh size, thus retaining fewer small individuals. To study this option, a bioeconomic simulation of a change in the gear selectivity from 100- to 120-mm minimum mesh size (MMS) was performed. The results show that the private perspective (profits) does not change. Furthermore, due to the lower retention of 120 mm MMS, the efficiency of a fishing day was reduced by 5% and 2.5%, from the point of view of capital and labour productivity, respectively. In contrast, gross revenues increased by 1.5% and crew compensation by 2%. Given a societal benefit of this change in the mesh size, this gain could be re-distributed to provide an incentive for selectivity improvements.La Política Pesquera Común de la Unión Europa ha introducido la prohibición de descartar, estableciendo que todo pescado por debajo de una talla de referencia no puede ser vendido para consumo humano directo. En una pesquería regulada a través de limitaciones del esfuerzo de pesca, la prohibición de descartar puede generar sobrecostes de manipulación, almacenamiento y desembarque adicionales. En una pesquería regulada a través de límites en las capturas, esta política podría incluso limitar los niveles de esfuerzo ya que todas las capturas deben ser deducidas de la cuota. En ambos casos, esta regulación puede reducir el resultado económico de las empresas, incluso en el caso de una pesquería mono-específica. Una posible solución sería aumentar el tamaño mínimo de la malla, y así reducir la retención de los individuos más pequeños. Con el fin de estudiar esta opción, se ha realizado una simulación bioeconómica de un cambio en el tamaño mínimo de la malla de 100 a 120-mm. Los resultados muestran cómo la perspectiva económica privada (beneficios) no varía. Más aun, debido a la menor retención de la malla de 120 mm, la eficiencia de un día de pesca se ve reducida en un 5% y en un 2.5%, desde el punto de vista de la productividad del capital y del trabajo, respectivamente. Por el contrario, los beneficios brutos aumentan un 1.5% y la remuneración al trabajo en un 2%. Debido a la existencia de un beneficio social, la ganancia podría ser redistribuida para así ofrecer un incentivo a esta mejora de la selectividad

A bayesian estimation of the economic effects of the Common Fisheries Policy on the Galician Fleet: a dynamic stochastic general equilibrium approach

What would have happened if a relatively looser fisheries policy had been implemented in the European Union (EU)? Using Bayesian methods a Dynamic Stochastic General Equilibrium (DSGE) model is estimated to assess the impact of the European Common Fisheries Policy (CFP) on the economic performance of a Galician (north- west of Spain) fleet highly dependant on the EU Atlantic southern stock of hake. Our counterfactual analysis shows that if a less effective CFP had been implemented during the period 1986–2012, fishing opportunities would have increased, leading to an increase in labour hours of 4.87%. However, this increase in fishing activity would have worsened the profitability of the fleet, dropping wages and rental price of capital by 6.79% and 0.88%, respectively. Welfare would also be negatively affected since, in addition to the increase in hours worked, consumption would have reduced by 0.59%.Da-Rocha, García-Cutrín and Gutiérrez acknowledge financial support from the European Commission (MINOUW, project H2020-SFS-2014-2, number 634495) and the Spanish Ministry of the Economy, Industry and Competitiveness (ECO2016-78819-R, AEI/FEDER, UE). Prellezo acknowledges financial support from the Basque Government (Department of Economic Development and Infrastructures of the Basque Government). Da-Rocha and García-Cutrín also acknowledge financial support from Xunta de Galicia (GRC 2015/014 and ECOBAS). Gutiérrez also acknowledges financial support from the Basque Government (MacLab IT-793-13). This publication reflects the views of the authors only and none of the funding parties may be held liable for any use which may be made of the information contained therein

To shape or to be shaped : engaging stakeholders in fishery management advice

The purpose of this paper is to assess the effectiveness of the collaboration between stakeholders and scientists in the construction of a bio-economic model to simulate management strategies for the fisheries in Iberian Atlantic waters. For three years, different stakeholders were involved in a model development study, participating in meetings, surveys and workshops. Participatory modelling involved the definition of objectives and priorities of stakeholders, a qualitative evaluation and validation of the model for use by decision-makers, and an iterative process with the fishing sector to interpret results and introduce new scenarios for numerical simulation. The results showed that the objectives of the participating stakeholders differed. Incorporating objectives into the design of the model and prioritising them was a challenging task. We showed that the parameterization of the model and the analysis of the scenarios results could be improved by the fishers’ input: e.g. ray and skate stocks were explicitly included in the model; and the behaviour of fleet dynamics proved much more complex than assumed in any traditional modelling approach. Overall, this study demonstrated that stakeholder engagement through dialogue and many interactions was beneficial for both, scientists and the fishing industry. The researchers obtained a final refined model and the fishing industry benefited for participating in a process, which enables them to influence decisions that may affect them directly (to shape) whereas non-participatory processes lead to management strategies being imposed on stakeholders (to be shaped)

A multi-stock harvest control rule based on "pretty good yield" ranges to support mixed-fisheries management

Advice for commercially exploited fish stocks is usually given on a stock-by-stock basis. In light of the ecosystem-based fisheries management, the need to move towards a holistic approach has been largely acknowledged. In addition, the discard bans in some countries requires consistent catch advice among stocks to mitigate choke species limiting fisheries activity. In this context, in 2015, the European Commission proposed the use of fishing mortality ranges around fishing mortality targets to give flexibility to the catch advice system and improve the use of fishing opportunities in mixed-fisheries. We present a multi-stock harvest control rule (HCR) that uses single stock assessment results and fishing mortality ranges to generate a consistent catch advice among stocks. We tested the performance of the HCR in two different case studies. An artificial case study with three stocks exploited simultaneously by a single fleet and the demersal mixed-fishery operating in Bay of Biscay and Celtic Sea. The HCR produced consistent catch advice among stocks when there was only a single fleet exploiting them. Even more, the HCR removed the impact of the discard ban. However, in a multi-fleet framework the performance of the HCR varied depending on the characteristics of the fleets

Measuring the value of ecosystem-based fishery management using financial portfolio theory

We highlight the potential benefits of adopting Ecosystem-based Fishery Management (EBFM). We compare the EBFM implementation with the more traditional single-stock approach. We show the contribution of the portfolio theory to the EBFM, which can be achieved by selecting an optimal portfolio to maximise the average revenues and minimise the variance. We use this approach to construct two frontiers: the ecosystem efficient frontier, which considers stock interactions (the variance-covariance matrix), and the stock efficient frontier,only considering individual stock variances. We also define two risk gaps. The first gap shows the reduction in the standard deviation per unit of revenuethat the fleet could have achieved if they had decided to use the optimal portfolio of the stock frontier instead ofthe historical portfolio. The second gap reflects the reduction in the standard deviation per unit of revenue when the management moves from the stock frontier to the ecosystem frontier portfolio. This approach is adapted to the Basque inshore fleet. According to our results, taking the single-stock approach as the benchmark, the EBFM would obtain the same historical revenue while reducing the risk by 23%.Alternatively, allowing the same level of risk, it could achieve a 21% increase in revenues.This work has received funding from Basque Government Department of Education (Grant IT-799-13). I. Carmona has benefited from a grant of the Department of Economic Development and Competitiveness of the Basque Government. A. Ansuategi, J.M. Chamorro and M. Escapa also thank financial support from the University of the Basque Country (Grant GIU 18-136) and from the Spanish Ministry of Science, Innovation and Universities (Grant RTI2018-093352-B-I00)

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

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