Open Ocean Aquaculture in Offshore Wind Farms

Study I

The feasibility study deals, on theoretical basis, with the potential multifunctional use of planned offshore-windfarms with commercial marine aquaculture (open ocean aquaculture) in the North Sea area. Exclusively, literature data from existing international experiences are reviewed here, as well as the output of several discussions with experts.

Firstly, the study reviews the current “state of the art” of open ocean aquaculture. The data was derived from existing projects within the international scientific community, which focused on candidate organisms, and dealt with offshore technology and maintenance aspects. Choice of location and infrastructure needed was also extracted from the findings of these projects. It became clear, that, in terms of commercial marine aquaculture, Germany, in comparison to many other maritime countries throughout the world, has to date little knowledge and background. Only one offshore aquaculture project nearby the Island of Helgoland was carried out. The current complicated and even counteractive national jurisdiction is identified being one of the main reasons for this lack of knowledge and experience. Next, the vast array of marine protected areas, national parks, as well as input of urban waste water adds to the calamity. However, especially the hydrodynamics of the North Sea play a key role as hindrance of establishing commercial marine aquaculture in Germany.

Secondly, the study carries out a selection of parameters, which need to be met during the decision-making of the location and construction of an offshore aquaculture farm. Next to geo-physical parameters, as wave parameters and local current profiles, other abiotic parameter, such as degree of contamination through urban waste water are addressed. Additionally, certain biological factors, such as plankton load and the concentration of chlorophyll within the possible locations were derived from existing data sets. A synthesis from these above parameters allowed the identification of suited candidates for a commercially running offshore-aquaculture. It is suggested to employ the cultivation of mussel (Mytilus edulis) and pacific oyster (Crassostrea gigas), as such a culture could be run extensively in the offshore region and the work-labour being mini mal. Similar accounts for seaweed, such as Saccharina latissima (Laminaria saccharina) and Palmaria palmata.

Thirdly, the study looked upon the possible selling market of the offshore aquaculture and their candidates in comparison to the performance of existing conventional operated farms in coastal waters. Main focus was placed on existing experience within the European community. It was put out, that a strong market exists for the suggested brown algae and red algae, which is likely to expand in the near future. The latter species can also be directly sold to the consumer as healthy food. However, one of the major elements for the economic success of the culture is the decision of the right location of an aquaculture. Here, factors like rapid accessibility due to shorter distances to the main land and available infrastructure need to be closely considered. Furthermore harbours with a good transport network and processing industries are, next to the direct local environmental factors at a specific wind farm, crucial factors. Thus, some of the wind farms, which are closer to the coastal areas economically more compatible as farm locations further off within the exclusive economic zone (EEZ). These factors, next to good management of the culture, are directly linked to the economic success of the activity.

The feasibility study closes with a final evaluation of all factors, which are critical for the development of a commercial offshore aquaculture in combination with the planned wind farms in the North Sea region.

Additional Content

Mytilus edulis

Crassostrea gigas

Saccharina latissima (Laminaria saccharina)

Palmaria palmata