부산대학교 도서관

The recently proposed ‘Real-Time Incentive (RTI)’ fisheries-management approach replaces catch or landings quotas and days-at-sea limitations with a single allowance of fishing-impact credits (‘RTIs’). According to this concept, fishing mortality rates of multiple species and impacts on the ecosystem are regulated through a single ‘currency’. Fishers can fish where and when they want and spend their allocated RTIs according to spatiotemporally varying tariffs. Managers set the tariffs based on agreed target mortality rates of multiple species, using knowledge of the spatiotemporally varying catchabilities of the various species caught or impacted in a mixed fishery. We explore algorithms for combining real-time CPUE data of up to four different species in a conceptual simulation model. The simulations indicate that RTI may perform better than several traditional management systems, such as broad-brush effort restrictions, Total Allowable Catches and Total Allowable Landings, in terms of controlling harvest rates of several species in a mixed fishery with differing catchabilities, while at the same time limiting impact on a vulnerable species or ecosystem elements. Performance weakens with greater spatial overlap of the ‘choke’ and other species, and also when fish migrate. Real-time updating requires that local CPUE levels in a given time step are predictive of catchabilities in the following time step. Historical information may be more accurate than real-time information if migration patterns are similar year-on-year. RTI allows the fishers to derive the balance between limiting mortality on choke and vulnerable species and optimally exploiting others because it internalises the cost of undesirable outcomes. In the light of the Ecosystem Based Approach to Fisheries Management, and in particular in the context of the European Union landings obligation, the integrated RTI fisheries management approach could offer a practical solution that addresses some of the problems inherent in a multi-objective fishery system. RTI is ready for case-specific testing. [ABSTRACT FROM AUTHOR]