Evaluation of FMSY ranges as a tool to combine long-term single-stock targets with flexible, short-term, mixed-fisheries management requirements
The 2013 reform of the Common European Fisheries Policy set as a goal to achieve an exploitation rate consistent with maximum sustainable yield (FMSY) by 2020 at the latest for all fish stocks.
However, achieving single species maximum sustainable yield (MSY) in complex fisheries targeting multiple species (mixed fisheries) is challenging because achieving the objective for one species may mean missing the objective for another. An example is the mixed demersal roundfish fisheries in the North Sea where a fisheries targeting North Sea haddock have contributed to a decline in the North Sea cod stock, and discards have increased as the cod quota were reduced.
Mixed-fisheries are challenging
Recognizing this fundamental mixed-fisheries issue, new approaches have emerged out of intense political, institutional, and scientific activity. A task force comprising the three main EU institutions (EU Commission, EU Parliament, and EU Council of Fisheries Ministers) suggested using ranges of or around FMSY as flexible targets of “pretty good yield” for the regional management plans, thus considering MSY as a desirable multidimensional area rather than a point estimate, which would allow for more flexibility in management targets.
A new study, led by Clara Ulrich as part a EU funded Myfish-project, recently published in the ICES Journal of Marine Science, investigates potential of FMSY ranges to combine long-term single-stock targets with flexible, short-term, mixed-fisheries management requirements applied to the main North Sea demersal stocks
The objectives are to evaluate the ability of using FMSY ranges to diminish the conflict between MSY management of single stocks and the possibility to deliver operational regional management based on mixed-fisheries considerations, Professor Clara Ulrich, DTU Aqua and co-authors write:
“Our approach is independent of the actual definition of MSY ranges, and could be applied to any defined interval. Ultimately, the concept of ranges could be extended and potentially asymmetrized to include other ecological and economic considerations.”
The authors show that sustained fishing at the upper bound of the range may lead to unacceptable risks when technical interactions occur. Consequently, an objective method is suggested that provides an optimal set of fishing mortality within the range, minimizing the risk of total allowable catch mismatches among stocks captured within mixed fisheries, and addressing explicitly the trade-offs between the most and least productive stocks.
The ICES Journal paper:
Clara Ulrich, Youen Vermard , Paul J. Dolder, Thomas Brunel, Ernesto Jardim, Steven J. Holmes, Alexander Kempf, Lars O. Mortensen, Jan-Jaap Poos, and Anna Rindorf: Achieving maximum sustainable yield in mixed fisheries: a management approach for the North Sea demersal fisheries
ICES Journal of Marine Science (2016), doi:10.1093/icesjms/fsw126
http://icesjms.oxfordjournals.org/content/early/2016/08/03/icesjms.fsw126.full.pdf?keytype=ref&%2520ijkey=X4f0fEL5LGg2FU1