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Research article - Peer-reviewed, 2019

Designing spawning closures can be complicated: Experience from cod in the Baltic Sea

Eero, Margit; Zimmermann, Christopher; Hinrichsen, Hans-Harald; Hjelm, Joakim; Huwer, Bastian; Hussy, Karin; Koster, Friedrich W.; Margonski, Piotr; Plikshs, Maris; Storr-Paulsen, Marie


Fisheries management measures often include spatio-temporal closures during the spawning period of the fish with an overarching aim of improving the stock status. The different mechanisms how a spawning closure potentially can influence the stock are often not explicitly considered when designing such closures. In this paper, we review and synthesize the available data and knowledge on potential effects of the implemented spawning closures on cod in the Baltic Sea. The Baltic cod example represents a relatively data rich case, which allows demonstrating how a closure might affect different parameters of stock status via different mechanisms, including potential unintended negative effects. We conclude that designing relatively small area closures appropriately is highly complex and data demanding, and may involve tradeoffs between positive and negative impacts on the stock. Seasonal closures covering most of the stock distribution during the spawning time are more robust to data limitations, and less likely to be counterproductive if suboptimally designed.


Spawning closure; Fisheries management; Recruitment; Stock structure; Baltic cod

Published in

Ocean and Coastal Management
2019, volume: 169, pages: 129-136

Authors' information

Eero, Margit
Technical University of Denmark (DTU)
Hinrichsen, Hans-Harald
Helmholtz Centre for Ocean Research (GEOMAR)
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Huwer, Bastian
Technical University of Denmark (DTU)
Hüssy, Karin
Technical University of Denmark (DTU)
Köster, Friedrich W.
Technical University of Denmark (DTU)
Margonski, Piotr
National Marine Fisheries Research Institute
Plikshs, Maris
Institute of Food Safety, Animal Health and Environment (BIOR)
Storr-Paulsen, Marie
Technical University of Denmark (DTU)
Zimmerman, Christopher
Thünen Institute of Baltic Sea Fisheries

UKÄ Subject classification

Fish and Aquacultural Science

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