Robust, ecological-economic multispecies management of Central Baltic fishery resources

The Baltic fisheries are in distress. In the Central Baltic, fisheries management is challenged by reduced cod stock productivity, and altered species interactions. Here, we use an age-structured, ecological-economic multispecies model, which includes latest biological and economic knowledge, to advance our understanding of optimal fisheries management and related trade-offs between user groups under such altered conditions. We contribute to the scientific discussion (i) by showing that the economic importance and optimal stock size of cod largely decreased under prevailing conditions, while clupeids increased in importance. (ii) We challenge the current MSY management objective in a multispecies setting (MMSY) and suggest that an economic multispecies management objective (MMEY) might be more useful for setting future management targets. (iii) We identify new trade-offs and synergies by including a consumer perspective: There is a win-win situation for ecological conservation, and profits in the fishery, while fishery management faces trade-offs between these two on the one hand, and consumer surplus on the other hand. (iv) Finally, we suggest an easy to implement new management approach, called robust management, which is capable of better dealing with variability and time-trends in recruitment, as observed for cod, in order to safeguard the Central Baltic fishery resources.