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Institute of

OF Baltic Sea Fisheries


marEEshift - Marine ecological economic systems in the Western Baltic Sea


marEEshiftMarine ecological-economic systems in the Western Baltic Sea and beyond: Shifting the baseline to a regime of sustainability

Cod and herring are important target species for the recreational and commercial fisheries in the Baltic Sea. Both fish stocks are in crisis, and science is not yet able to fully explain the environmental and anthropogenic drivers of the stock changes. MarEEshift aims to identify social, ecological and economical tipping points in the Western Baltic Sea ecoregion and to investigate the stakeholder's perceived cause and effect mechanisms regarding the western Baltic cod management as basis for a regime of sustainability.

Background and Objective

The social-ecological system „Baltic Sea“ is subject to constant changes in environmental conditions, anthropogenic pressures, as well as political and legal framework conditions. The interactions between human activities and environmental changes can trigger abrupt changes in ecosystem status (tipping points), which may result in a cascade of further social, economic and institutional tipping points. If impacts occur with time delay, relevant threshold values may be detected not until the tipping points have already been exceeded. At present, the cod and herring stocks of the Baltic Sea are subject to commercial and recreational fishing and close to collapse. The current fisheries management takes recreational fishing into account, but is confronted with the fact that recreational and commercial fisheries differ in their dynamics, objectives and preferences. It is therefore questionable whether the management approaches designed for commercial fisheries can efficiently address the needs of recreational fisheries or create conflicts between stakeholder groups and increase environmental, social and economic risks. MarEEshift aims to develop and operationalize a stable management system for the mixed commercial and recreational cod fishery in the western Baltic Sea. The project first aims to understand the drivers influencing the resilience of the marine social-ecological systems. Then, management approaches able to shift the social-ecological system into a more sustainable state are to be identified.


The Thuenen-Institute of Baltic Sea Fisheries cooperates with researchers from multiple disciplines. Time serious analysis will be applied to assess changes in recreational fishing behaviour and to identify relevant tipping points. The main responsibility of the Thünen-OF is the planning and implementation of a workshop series with different stakeholders from recreational and commercial fisheries, environmental NGOs and fisheries management. 

Our Research Questions

The workshops will serve the following objectives: (1) The exploration of stakeholders understanding for social-ecological interactions influencing cod stocks, (2) the co-production and exchange of knowledge and finally (3) the development of a common concept of sustainable management.

Preliminary Results

In the individual workshops, the respective system understanding of the different stakeholder groups was developed. This allowed the identification of major influences impacting on the Baltic Sea. Among others, predator pressure, water quality (nutrient inputs, temperature, algal bloom, salinity), spawning & nursery areas, anthropogenic use (energy production, noise), cod food, as well as parasites were mentioned here, whereby the influencing factors were evaluated differently between the stakeholder groups. Cod removals by commercial and recreational fisheries were also perceived differently by the different groups.
Furthermore, existing measures were discussed and new ideas for possible management options were collected, which will be discussed together in the planned final workshop.

Involved external Thünen-Partners

  • Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
    (Berlin, Deutschland)
  • Universität Hamburg
    (Hamburg, Deutschland)
  • Albert-Ludwig Universität Freiburg
    (Freiburg, Deutschland)
  • Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv), Halle-Jena-Leipzig
    (Leipzig, Deutschland)

Funding Body

  • Federal Ministry of Education and Research (BMBF)
    (national, öffentlich)


5.2019 - 4.2023

More Information

Project status: ongoing


  1. 0

    Lewin W-C, Weltersbach MS, Haase K, Arlinghaus R, Strehlow HV (2023) Change points in marine recreational fisheries - the impact of stock status and fisheries regulations: A case from the western Baltic Sea. Fish Res 258(Feb. 2023):106548, DOI:10.1016/j.fishres.2022.106548

  2. 1

    Lewin W-C, Weltersbach MS, Haase K, Riepe C, Strehlow HV (2023) Potential biases in angler diary data: The impact of the diarist recruitment process on participation rates, catch, harvest, and effort estimates. Fish Res 258(Feb. 2023):106551, DOI:10.1016/j.fishres.2022.106551

  3. 2

    Bronnmann J, Koemle D, Meyerhoff J, Weltersbach MS, Strehlow HV, Arlinghaus R (2023) Willingness to pay for harvest regulations and catch outcomes in recreational fisheries: A stated preference study of German cod anglers. Fish Res 259(März 2023):106536, DOI:10.1016/j.fishres.2022.106536

  4. 3

    Haase K, Weltersbach MS, Lewin W-C, Zimmermann C, Strehlow HV (2022) Potential effects of management options on marine recreational fisheries - the example of the western Baltic cod fishery. ICES J Mar Sci 79(3):661-676, DOI:10.1093/icesjms/fsac012

  5. 4

    Lewin W-C, Weltersbach MS, Haase K, Riepe C, Skov C, Gundelund C, Strehlow HV (2021) Comparing on-site and off-site survey data to investigate survey biases in recreational fisheries data. ICES J Mar Sci 78(7):2528-2546, DOI:10.1093/icesjms/fsab131

  6. 5

    Skov C, Hyder K, Gundelund C, Ahvonen A, Baudrier J, Borch T, Carvalho Sde, Erzini K, Ferter K, Grati F, Hammen T van der, Hinriksson J, Houtman R, Kagervall A, Kapiris K, Karlsson M, Lejk AM, Lyle JM, Strehlow HV, Weltersbach MS, et al (2021) Expert opinion on using angler Smartphone apps to inform marine fisheries management: status, prospects, and needs. ICES J Mar Sci 78(3):967-978, DOI:10.1093/icesjms/fsaa243

  7. 6

    Pita P, Ainsworth GB, Alba B, Anderson AB, Antelo M, Asos J, Artetxe I, Baudrier J, Castro JJ, Chicharro B, Erzini K, Ferter K, Freitas M, Garcia-de-la-Fuente L, Garcia-Charton J, Gimenez-Casalduero M, Grau AM, Diogo HM, Strehlow HV, Weltersbach MS, et al (2021) First assessment of the impacts of the COVID-19 pandemic on global marine recreational fisheries. Front Mar Sci 8:735741, DOI:10.3389/fmars.2021.735741

  8. 7

    Weltersbach MS, Riepe C, Lewin W-C, Strehlow HV (2021) Ökologische, soziale und ökonomische Dimensionen des Meeresangelns in Deutschland. Braunschweig: Johann Heinrich von Thünen-Institut, 210 p, Thünen Rep 83, DOI:10.3220/REP1611578297000

  9. 8

    Lewin W-C, Weltersbach MS, Haase K, Strehlow HV (2021) Who travels how far: German Baltic sea anglers’ travel distances as precondition for fisheries management and coastal spatial planning. Ocean Coastal Manag 209:105640, DOI:10.1016/j.ocecoaman.2021.105640

  10. 9

    Lewin W-C, Weltersbach MS, Denfeld G, Strehlow HV (2020) Recreational anglers’ perceptions, attitudes and estimated contribution to angling related marine litter in the German Baltic Sea. J Environ Manag 272:111062, DOI:10.1016/j.jenvman.2020.111062

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