Comparing economic and biological management objectives in the commercial Baltic salmon fisheries

This paper compares two fisheries management objectives recognized in the literature and applied in practice: maximum sustainable yield (MSY) and maximum economic yield (MEY). The European Union Common Fisheries Policy (CFP) sets the minimum target of fish populations at the MSY level, defined as the stock level that maximizes the fish catch. Although MSY is useful in nudging over-harvested stocks back to biologically sustainable levels, the CFP requires the harvested stocks to be maintained above levels that can produce MSY without addressing the exact definition of “above MSY”. One possibility for maintaining fish stocks above MSY is to apply the maximum economic yield (MEY) that maximizes the discounted net present value of the fishery. Comparison of the economic and ecological outcomes of the two objectives in the Northern Baltic salmon fishery is conducted by applying a dynamic optimization model coupled with age-structured salmon stock dynamics. The results are further tested for the changes in stock-recruitment parameters, and related to the precautionary management target of reaching 75% smolt production capacity. A sensitivity analysis for the economic parameter values is conducted. The results show that as a target, MEY performs better than MSY in both conserving the stocks and providing economic viability for the fishers. Targeting MEY while keeping MSY at hand as a minimum biological objective was found to be a pragmatic objective that is in line with the goals of the CFP and the EU Blue Growth Strategy.