Testing the CEAF (Common Environmental Assessment Framework) modelling tool on three SEANSE scenarios: collision mortality and displacement of four seabird species


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This study, conducted within the SEANSE project, is a test of the CEAF modelling tool (Common Environmental Assessment Framework) that reports calculations on the cumulative collision and mortality displacement incidence of four seabird species (Rissa tridactyla, Larus fuscus, Gavia stellate, Uria aalge) for three different scenarios of offshore wind farm development in the southern part of the North Sea.

Sea Basin(s): 
December 2019
Application in MSP: 
Taken into account in an MSP process
Nature protection
Offshore renewable energy production
Type of Issue: 
Coexistence of uses
Ecosystem-based approach
Environment aspects
Type of practice: 
Stage of MSP cycle: 
Analyse spatial aspects
Cross-border / trans-national aspect: 
Coherence with other processes: 
Habitats and Birds Directive
Renewable Energy Directive
Strategic Environmental Assessment

Questions this practice may help answer:

  • How to assess offshore wind farm impact on sea bird populations?
  • What improvements could be made to the CEAF modelling tool? 

Implementation Context:

This study was conducted in the framework of the SEANSE project, whose objective was to "develop a coherent (logical and well-organised) approach to Strategic Environmental Assessments (SEAs), with a focus on renewable energy in support of the development and effective implementation of MSPs."

Aspects / Objectives:

The main aim of this study was to test whether the CEAF tool would be able to provide reliable and reproducible data on the cumulative collision mortality of black-legged kittiwake and lesser black-backed gull, as well as the cumulative number of displaced individuals of red-throated diver and common guillemot, for three different scenarios of offshore wind farm development. It also aimed at contributing to the development of the cumulation modelling tool.


Methods for collision and displacement calculations use distribution data originating from ESAS/MWLT monitoring programmes as a main input.

Main Outputs / Results:

The report explicitly focuses on the evaluation and possible improvements of an existing model and the way this model can be used to determine population effects. It discusses how different methods or new insights into certain knowledge gaps could further improve the accuracy of the estimated mortality numbers. The report then provides recommendations on how these cumulative numbers (collision mortality and numbers of displaced birds, respectively) can be assessed in terms of impacts at the population level.


The recommendations for improvements of the CEAF modelling tool can serve as an input for future SEAs and EIAs of offshore wind projects with regards to impacts on bird populations.

Responsible Entity:

Bureau Waardenburg, Ecologie & Landschap - Netherlands

Costs / Funding Source:

Co-funded by the European Maritime and Fisheries Fund (EMFF)

Contact person:

Dr. A. Gyimesi

Rijkswaterstaat Water, Verkeer & Leefomgeving (WVL)

Postbus 2232, 3500 GE Utrecht