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

Rudi Voss,Stefan Neuenfeldt,Martin Quaas,Henn Ojaveer

doi:10.1093/icesjms/fsab251

Abstract

Abstract 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.

Highlights

The Baltic Sea is one of the largest brackish water bodies in the World with a century-long history of fishing (MacKenzie et al, 2011)
Trade-offs between management objectives are obvious for the 2020 comparison: maximum sustainable yield (MMSY) yields higher harvest and higher fishing effort, but maximum multispecies economic yield (MMEY) results in higher stock sizes
The identification of trade-offs as well as potential synergies among multiple ecosystem goods and services is a central issue in ecosystembased management (EBM; McLeod and Leslie, 2009) and it is ur

Summary

Introduction

The Baltic Sea is one of the largest brackish water bodies in the World with a century-long history of fishing (MacKenzie et al, 2011). The central stock, which we address here, was larger in size and distribution, and contributed more to the total Baltic cod harvest. It largely overlaps with a herring stock, which is assessed for SD 25–29 and 32, excluding a distinct Gulf of Riga population. The sprat population is assessed for the whole Baltic Sea, i.e. SD 22–32 It has its main distribution range east of Bornholm, thereby showing a large overlap to the Central Baltic cod and herring populations. We are addressing these three stocks in our multispecies model

Methods

Results

Conclusion