Bioeconomic Losses from Overharvesting Tuna

The harvest from the world's marine capture fisheries appears to have peaked, with substantialovercapacity in many fisheries and ongoing creep in fishing effort that continues to erode profits.Using a dynamic programming approach that explicitly accounts for nonlinear stock effects, we showthat in one of the world's largest fisheries - tunas of the western and central Pacific - adopting abiomass target maximising the discounted economic profits (BMEY) from fishing would result in alarger biomass than current levels or traditional biological targets. The gains from stock rebuilding tofishers alone are calculated to be in excess of $3 billion over a fifty year planning horizon. Adopting adynamic BMEY target coupled with incentives that would allow fishers to be the beneficiaries of stockrebuilding offers the promise of a win-win - larger and sustainable fish stocks and more profitablefisheries.