A bio-economic evaluation of different management measures for the Mediterranean swordfish

The biological and economic implications of different management measures concerning the Mediterranean swordfish stock were evaluated by means of simulations performed under the Fisheries Language in R (FLR) framework. Six different scenarios were examined including Mediterranean-wide seasonal closures of different duration and an effort reduction scheme. Recruitment was assumed to vary in levels either predicted by a Beverton–Holt stock–recruitment relationship or around an average value estimated from the latest assessment accomplished by the International Commission for the Conservation of Atlantic Tunas (ICCAT). Simulations projected the levels of landings, spawning stock biomass (SSB), gross and net revenue for a period of twenty years. Considering the estimated statistical uncertainty, gains in terms of landings and SSB from short fishery closures (e.g. one month) will be negligible. On the contrary, seasonal closures of at least four months would result in important long-term gains, which are more profound in the case of SSB and net revenue. The ICCAT convention objectives concerning SSB, can only be met with drastic closures (i.e. six months). However, drastic closures would result in short-term decreases in landings and revenues, which should be taken into account before such measures are adopted.