Measuring fishing capacity of red seabream in the Strait of Gibraltar [Spain]: Parametric and non-parametric approaches | Medición de la capacidad de pesca de la flota de voraz del Estrecho de Gibraltar: enfoques paramétricos y no paramétricos

الأسبانية؛ قشتالية. La alta rentabilidad y movilidad de los buques inscritos en el Censo de Flota Operativa artesanal provocó una expansión significativa de la flota voracera que faena en aguas del Estrecho de Gibraltar durante el período 1983-1995. Era evidente en 1998 que la pesquería de voraz (Pagellus bogaraveo, Brünnich 1768) estaba siendo sobreexplotada. Este hecho motivó la elaboración y aplicación de dos planes de recuperación en los períodos 1999-2002 y 2003-2005 tendentes a garantizar la sostenibilidad bioeconómica de la pesquería y reducir la sobrecapacidad de la flota que la explota. Este artículo tiene como objeto evaluar el efecto sobre la capacidad de pesca del primer plan de recuperación y calcular la sobrecapacidad de la flota voracera al principio del segundo plan de recuperación usando las técnicas Pico a Pico, Análisis Envolvente de Datos y Análisis de Fronteras Estocásticas. Los resultados de esta aplicación muestran que el primer plan de recuperación ha logrado frenar la expansión de la flota voracera reduciendo su capacidad de pesca, pese a que a principios del segundo plan de recuperación continúa existiendo sobrecapacidad de la flota. Se concluye señalando la necesidad de introducir medidas de gestión que modifiquen los incentivos económicos de los pescadores a maximizar su captura individualmente, especialmente aquellas que progresen más en la implicación de los pescadores en la gestión de la pesquería.

إنجليزي. High profitability, vessel mobility and open access resulted in an increase in total harvesting capacity in the red seabream fishery (Pagellus bogaraveo, Brünnich, 1768) during the period 1983-1998. In 1998 it was evident that the fishery was overexploited and two recovery plans aimed at sustainability and reducing overcapacity of the fishery were implemented in periods 1999-2002 and 2003-2005. The first recovery plan introduced a limited license program to restrict access to the fishery, fishing gear restrictions, a cap on the number of fishing trips, incentives to leave fishing employment, and a size limitation on fish caught. An advisory board was formed, composed of fishermen and other interest groups. The second recovery plan imposed a Total Allowable Catch (TAC) per year. This paper investigates the effects of the first recovery plan on fishing capacity and estimates overcapacity of the voracera fleet at the beginning of the second recovery plan. Fishing capacity and capacity utilization are determined by Peak to Peak, Stochastic Frontier Analysis (SFA) and Data Envelopment Analysis (DEA) techniques. The Peak to Peak technique is based on the identification of peaks (relative maximum outputs) using historical information of the fishery and assuming that capacity is completely used in peaks periods. Peak to Peak is an appropriate technique only when data are limited. Fare et al. (1989) developed a two-stage procedure based on the efficiency and productivity analysis non-parametric technique Data Envelopment Analysis (DEA) to calculate production capacity and capacity utilization that was first applied to fisheries. This procedure imposes full utilization of variable productive inputs in a standard DEA linear problem to determine fishing capacity and observed capacity utilization in a first stage. A standard DEA linear program is run in a second stage to determine efficient capacity utilization. Stochastic Frontier Analysis is parametric technique of the efficiency and productivity analysis. Two procedures have been used in the paper to measure fishing capacity and capacity utilization. The first procedure (Pure SFA) estimates an SFA model without restricting variable inputs in a first stage to determine fishing capacity and observed capacity utilization. A standard SFA model is estimated to obtain efficient capacity utilization in a second stage. The second procedure (Mix DEA-SFA) determines the ratio of utilization of variable inputs using a DEA linear program, where full utilization of variable inputs is imposed. In a second stage, a standard SFA model is estimated and evaluated to determine fishing capacity and observed and efficient capacity utilization using the ratio of utilization of variable inputs calculated from the DEA first stage. The results from the three techniques are compared. Results suggest that management measures applied in the fishery at the end of 1998 have had a positive effect on the objective of reducing fishing capacity of this fleet. Nonetheless, it is worth noting that management measures implemented in the fishery may not have a significant effect on reducing fishing capacity in the long term. It is necessary to introduce measures that change the incentives of fishermen and to make further progress involving fishermen in the management of the resource.