Jakob Tougaard, Emily T. Griffiths, Michael Ladegaard, Charlotte Rose Findlay, Mel Cosentino, Signe Sveegaard, Line Kyhn, Julia Carlström, Kylie Owen and Pia Eriksson 2023. Effects of rerouting shipping lanes in Kattegat on the underwater soundscape. Report to the Danish Environmental Protection Agency on EMFF project
TANGO. Aarhus University, DCE – Danish Centre for Environment and Energy, 63 pp. Scientific Report No. 535 http://dce2.au.dk/pub/SR535.pdf
The Tango project has documented changes to the underwater soundscape of eastern Kattegat in the Baltic Sea caused by a major change in the shipping lanes in summer 2020. The density of ships from AIS data showed a diversion of a large fraction of ships from the existing route T into the new Route S, closer to the coast of Sweden. Measurements of underwater noise close to the shipping lanes showed decreases in noise levels across all frequency bands along Route T and increases across all frequency bands along Route S. Monthly modelled soundscape maps showed that the area exposed to ship noise was largest in winter months, where also increases to the affected area due to rerouting were largest. The impacted area was generally smaller in summer and effect of re-routing positive (smaller area impacted by noise). Passive acoustic monitoring of harbour porpoises along the shipping lanes did not show overall changes in the distribution of porpoises correlated with the shipping lane changes, but documented short-lived reactions of porpoises to the passage of individual ships.
