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.

Fishing fleets competing for quota in the Eastern Channel: an IBM, bio‐economic, approach

The European Commission is considering the imposition of a discard ban to preserve vulnerable and economically important fish stocks. We explored the potential effects of a discard ban in mixed fisheries management using the French mixed fisheries in the Eastern English Channel as a model system. We examined in particular the performance of 2 different management scenarios: (1) individual quota management with a tolerance for discarding and (2) individual quota management in combination with a discard ban, using a dynamic state variable model. The model evaluates a time series of decisions taken by fishers to maximise profits within management constraints. Compliance to management was tested by applying an in-height varying fine for exceeding the quota. We then evaluated the consequences of individual cod quota in both scenarios with respect to over-quota discarding, spatial and temporal effort allocation and switching between métiers.


Individual quota management without a discard ban hardly influenced fishers’ behaviour as they could fully utilise cod quota and continue fishing while discarding cod. In contrast, a discard ban forced fishers to reallocate effort to areas and weeks in which cod catch is low, at the expense of lower revenue.

In the study, two indicators of fishery success, i.e. effort and net revenue, were weighed against cod catch. Reducing individual quota (IQ) while allowing cod discards upholds effort, net revenue and cod catches for both fleets. The slight decrease in net revenue for trawlers can be related to reduced cod landings. In contrast, imposing a discard ban clearly affects both indicators and cod catch.

Relevance for Policy:
  • Common Fisheries Policy
Data availability:

Availability:  Study published as Batsleer et al. 2013 in Marine Ecology Progress Series, 479: 177–190.

Lead Author:

J. Batsleer & J.J. Poos
Institute for Marine Resources and Ecosystem Studies (DLO-IMARES)
Date of research: June 2014

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Social economic impact assessment for the future 

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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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