The ‚Stiftung Offshore Windenergie’ requested BioConsult SH in collaboration with ‚biola’ to study the subjects of protection resting birds and marine mammals in the frame of construction of the offshore test field Alpha Ventus according to the „Standards for the Environmental Impact Assessment“ of the BSH. Alpha Ventus is the first German offshore wind farm. It consists of twelve wind turbines, situated about 90km off the North Sea coast of Lower Saxony in the German Bight. The baseline survey started in spring 2008. The wind farm was constructed from April to August 2009.

With regard to marine mammals data were collected by means of aerial surveys, ship surveys and porpoise click detectors (T-PODs). T-PODs were installed at 12 different locations according to the standards of the Federal Maritime and Hydrographic Agency of Germany (BSH). Results of the baseline study in 2008 showed presence of porpoises in the entire study area almost every day. A clear 24 hours activity rhythm showed high activity during daylight hours and low activity during evening and night hours. In three sub-areas, including the construction area, relative porpoise density was similar in two consecutive years of investigation. Maximum densities were recorded in late winter and in autumn and the minimum density in June. Compared with this, the sea area ‚Borkum Riffgrund’ showed a consistently higher relative porpoise density with a (weak) maximum in summer (July).
Data on possible impacts during construction of the wind farm were analysed, and the results are coming soon.

Diederichs, A., M. J. Brandt, G. Nehls, M. Laczny, A. Hill & W. Piper (2010):
Auswirkungen des Baus des Offshore-Testfelds „alpha ventus“ auf marine Säugetiere. Im Auftrag der Stiftung Offshore-Windenergie.

Client: Stiftung Offshore-Windenergie