Marine Research Findings of the VECTORS Project

This website provides access to the research results of the VECTORS project, which can be used to support marine management decisions, policies and governance as well as future research and investment. VECTORS was a large scale project that brought together more than 200 expert researchers from 16 different countries. It examined the significant changes taking place in European seas, their causes, and the impacts they will have on society.

Endogenous risk of stock collapse and the rise and fall of the Great Fish Pact

This study makes important contributions to our theoretical understanding of what makes countries cooperate in fisheries agreements. The results are mixed. We find that previous approaches have made assumptions which lead to an underestimation of the incentives to cooperate but in other ways, they have overestimated the incentives to cooperate. Previous studies underestimate the potential for cooperation because they fail to take into account the risk of stock collapse. Stock collapse can occur due to overfishing, climate change, or invasive species. Cooperation is more attractive when these important issues are taken into account. However, previous studies have also failed to account the progressive changes in the size of the fish stock which occur after a country chooses to no longer cooperate. This results in a reduction in the incentives to cooperate.


The research shows that countries may wish to deplete slow growing stocks to extinction, thus strong regulation may be necessary. However, stocks which grow slowly, but not very slowly are more likely to be managed cooperatively. This suggests that considering the growth rate of stocks is vital for optimal regulation.

We construct a dynamic game theoretic model of fisheries based on the classic Great Fish War model. We adapt the model by including an endogenously determined risk of stock collapse. Thus, the greater the harvest, the greater the risk of collapse. We analyse the game numerically for diverse numbers of countries which are assumed to be homogenous for various growth and discount rates. We also consider different functions determining the probability of collapse and test the effects of relaxing the assumption that stock size immediately jumps from size to another depending on the choices of countries to cooperate.

Relevance for Policy:
  • Common Fisheries Policy

Lead Author:

Adam N. Walker
Institute for Marine Resources and Ecosystem Studies (DLO-IMARES)
Date of research: October 2014

Related articles:

Fish stock location and international agreements

Changes on stocks and management in saithe fishery 

Ecology - Economy interactions in fisheries 

Climate change: flatfish and shrimp fisheries 

Modelling fishing fleets competing for quota

Modelling fishing fleets competing for space

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This project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 266445
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