Aarhus University Seal / Aarhus Universitets segl

No. 289: Marine mammals in relation to the alternative route north of Bornholm Nord Stream 2 project. Baseline and assessment report

Tougaard, J., Galatius, A., Teilmann, J. & Sveegaard, S. 2018. Marine mammals in relation to the alternative route north of Bornholm Nord Stream 2 project. Baseline and assessment report. Aarhus University, DCE – Danish Centre for Environment and Energy, 70 pp. Scientific Report No. 289. http://dce2.au.dk/pub/SR289.pdf

Summary

An underwater pipeline, Nord Stream 2, is proposed to be constructed in Danish waters, along a route from the central Baltic, north around Bornholm and making landfall on the coast of Mecklenburg-Vorpommern, Germany. This report describes baseline data for abundance and sensitivity of marine mammals in the area: harbour porpoises, harbour seals and grey seals, as well as an assessment of likely impact by construction and operation of the pipeline on these species. Possible impacts include resuspension of sediment during construction and underwater noise from construction ships and pipeline. Underwater noise from clearing of world war 2 ammunition on the seabed, should this need arise, has potential for significant impact on marine mammals unless properly mitigated. All other impacts are considered to have either negligible or minor (insignificant) effects on the populations of marine mammals in the area, including the critically endangered population of harbour porpoises in the Baltic proper.