Aarhus University Seal / Aarhus Universitets segl

No. 237: Marine mammals in the Swedish and Danish Baltic Sea in relation to the Nord Stream 2 project. Expert Assessment

Sveegaard, S., Teilmann, J. & Tougaard, J. 2017. Marine mammals in the Swedish and Danish Baltic Sea in relation to the Nord Stream 2 project. Expert Assessment. Aarhus University, DCE – Danish Centre for Environment and Energy, 68 pp. Scientific Report from DCE – Danish Centre for Environment and Energy No. 237. http://dce2.au.dk/pub/SR237.pdf

Summary 

Nord Stream 2 AG (NSP2) is planning the construction of a second gas pipeline in the Baltic running from Russia to Germany. In this report, the potential impacts on marine mammals of the gas pipeline in Danish and Swedish waters, are assessed. The relevant marine mammal species are harbour porpoise and grey seal in Danish waters and harbour porpoise, grey seal, harbour seal and ringed seal in Swedish waters. The assessment is based on information and studies conducted during the Environmental Impact Assessments for marine mammals for Nord Stream, the NSP2 baseline report for marine mammals, models on sedimentation and underwater noise in Danish and Swedish waters as well as relevant literature. No new fieldwork was conducted. In the report, the pressures related to the periods of construction, precommissioning, commissioning and operation of the gas pipeline are described and assessed in relation to the sensitivity of marine mammals. The main impacts from planned activities are underwater noise, sediment spill and changes to the habitat. Impacts from unplanned activities are munition clearance, oil spill, gas leaks, and noise and disturbance from ice breaking support vessels. All impacts, except munition clearance, are assessed to have a negligible to minor impact. In case munition clearance is required, the noise from the explosions could have major impact, depending on the area and species.