Residence time and behaviour of sole and cod in the Offshore Wind farm Egmond aan Zee (OWEZ)

‘Noordzeewind’ (a Nuon and Shell Wind Energy consortium) exploits a wind farm with 36 wind turbines off the coast of Egmond aan Zee: the Offshore Wind farm Egmond aan Zee (OWEZ). This project serves to evaluate the economical, technical, ecological and social effects of offshore wind farms in general. To gather knowledge which will result from this project, a Monitoring and Evaluation Program (NSW6MEP) has been developed. Knowledge on environmental impact gained by this project will be made available to all parties involved in the realization of large6scale offshore wind farms. The construction and operation of offshore wind farms may result in possible negative impacts on fish populations, e.g. disturbance by noise or electromagnetic fields around cables, and consequent loss and degradation of habitats. On the other hand, due to the creation of new structures, i.e. additional habitats, that might act as artificial reefs or fish aggregation devices in combination with banning fisheries and shipping within wind farms, also positive impacts on fish populations are possible (Inger et al. 2009). In the latter case, wind farms might act as marine6protected areas or refuges for some fish species. The overall effect of the potential negative and positive impacts of the construction and operation of wind farms for fish is highly dependent on individual behavioural responses of fish to wind farms. This study focuses on exploring the potential benefits of the wind farm OWEZ, i.e. whether the wind farm can act as a refuge against fisheries for some fish species, by studying individual behaviour of fish during the operation phase of the wind farm. A key factor in this is individual residence time of fish within the wind farm. The longer individual fish spend in the wind farm, the stronger potential benefit of wind farms can be expected