The MINOS project: ecological assessments of possible impacts of offshore wind energy projects

The joint research project MINOS examines whether large-scale offshore wind farms within the German parts of the North and Baltic Seas affect or endanger harbour porpoises, common seals, and seabirds. The research results are expected to provide the basis for estimating and assessing the impacts of future wind farms. MINOS focuses on two items: recording the preferential habitats and migratory routes of these animals in the EEZ, and investigating the sensitivity of porpoises and seals to sound, in order to assess possible damage, displacement and disturbance. When evaluating overall impacts to these animals, any expected impact of offshore wind farms must be considered in the context of already existing stressors.

The goal of the research is not to prevent or to hamper wind farming, but to provide a profound and reproducible knowledge basis for assessment in order to facilitate the development of sustainable power generation. This decision will not be taken by biologists or geologists, but by authorities or in court.

Since harbour porpoises have an ultrasonic location system (like bats), they are very sensitive to underwater noise. The noise produced during the construction and operation of offshore wind turbines, could cause behavioural changes or even physical harm to these animals. Such disturbances could displace the porpoises from their feeding and breeding habitats or otherwise reduce their fitness due to higher stress. Similar effects could also be expected to apply to common seals. Preliminary results indicate that harbour porpoises and common seals avoid sources that emit sounds similar to that of wind turbines.

With regard to seabirds, MINOS has focused on divers and sea ducks, which have important wintering grounds in the North and Baltic Seas within the German EEZ. The construction of offshore wind farms within these areas should be assessed with regard to possible detrimental consequences caused by the loss or interruption of diver and sea duck resting and feeding habitats.

MINOS has also developed and expanded upon research and evaluation methods for future use in monitoring programmes. Resting seabirds and harbour porpoises were counted using low altitude aerial transect surveys. Complex mathematical modelling was used to estimate the abundance of animals. Similarly, ship surveys were also carried out. Telemetry was used to record spatial activity patterns of seals. Hearing tests were carried out with free-ranging porpoises and seals and their conspecifics in captivity. Finally, porpoise detectors (POD) were employed to detect the presence of porpoises in the vicinity. These detectors can function for several weeks, but cannot determine the relative number of animals; nonetheless, they provide important additional results to the numbers gained through airborne and at-sea surveys.

The above-described research has been conducted in seven separate subprojects, integrated into the MINOS-project and its successor, MINOSplus (see chapters 10, 11, 12 and 13). All projects were funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety.