Impact assessment of windmill parks on fisheries

DONG Wind Farm 1An on-going work is to apply and downscale the DISPLACE model to the commercially important and busy Western Baltic marine area where several utilisations of the sea currently coexist. In line with this it is evaluated to which extent the international plans for offshore windmill parks in the Baltic area are affecting the fishing opportunities per activity and fishing communities in the vicinity of the planned windmill sites.

Hence, preliminary data mining shows that the planned offshore windmill parks in the area do not really interfere with important fishing grounds for the Danish fisheries. A notable exception is the large ‘Kriegers Flak’ site (where turbines will be shared between Denmark, Germany and ultimately, Sweden). A windmill farm here will impact important existing fishing grounds.map_spatial_dependency_and_planned_windmillfarms_sitesTwo indices of spatial use by the Danish vessels (>12m) visiting the Kattegat and the Baltic Sea in 2012, (a) revenue of the vessel visiting the cells over the total revenue, and (b) revenue realized on the cells by the visiting vessels over the total revenue of the same vessels. The gradient colour shows low (blue) up to high (red) index values. The planned (from 2013) windmill parks given in purple polygons (Source: compiled by DTU-Aqua)

Indices of activity (margin figure) reveal that this area is not really an important area in terms of total revenue at the scale of the entire Danish fisheries because not visited by “big players”. By contrast the area is important for a large portion of vessels (likely conducting small scale fisheries) which realise a significant portion of their total 2012 revenue in the designated area. Accordingly, it will impact many fishing businesses and the local societies. If this impact leads to major disruption of the fishing activities and/or major consequences on the population dynamics should be further investigated by modelling applying the DISPLACE model.

The evaluation intends to cover the implications in terms of individual profitability, and also in terms of the sustainability of the exploitation of the main commercial stocks in the area (i.e. sprat, herring, cod and flatfish) and possibly the likely effect on the benthic communities from redirected bottom-disturbing activities. Integration of the Swedish and German vessels (also operating in the area) on top of the Danish ones is also planned to expand the impact evaluation.

DISPLACE – An individual-based model of fishing vessels

DISPLACE stands for a Dynamic, Individual-based model for Spatial fishing PLAnning and effort displaCEment. A paper in press can be found here

A wiki page has just been set up at to host documentation and links to the source code repository (in progress). Make it transparent, peer-checked and prone to cooperative development.

fishingThe DISPLACE project is attempting to develop and provide a platform primarly for research purposes to transform the fishermen’s detailed knowledge into models, evaluation tools and methods that can provide the fisheries with research and advice. We need also models that can serve as a basis for decision support tools for (fishery) managers.  Among other goals, economic benefit of stock replenishment and sustainable harvesting should be demonstrated. As a general rule, it is important to evaluate the combined ecological and economic impacts of fishery management before its implementation (i.e. impact assessment).



An individual-based model (IBM) on a per-vessel basis covering several fisheries and stocks is a benchmark tool capable of integrating fishermen’s decision-making processes when they face changes in fishery management, economic factors influencing the fishery, economic viability, and underlying stock conditions, including spatial and seasonal patterns in resource availability.