The overall purpose of the project is to contribute to sustainable marine protection and enhanced biodiversity in two protected areas in the Baltic Sea. Through collaboration, advocacy and communication work, the project also aims to strengthen marine protection and biodiversity in the Baltic Sea as a whole.
The role of the Swedish Museum of Natural History is centred around examining the impact of underwater noise on harbour porpoises, with the aim of identifying appropriate measures for the protection of harbour porpoises in the Natura 2000 site Hoburgs bank and the Midsea Banks in the Baltic Sea.
In the project, the Swedish Museum of Natural History collaborates with the Swedish Defence Research Agency (FOI), where we measure the acoustic presence of harbour porpoises and FOI measures underwater sound levels. We use models to determine how the underwater sound levels influence the detection rate of harbour porpoises, and how this changes between seasons. Harbour porpoises have strong seasonal movement patterns, and may be more sensitive to noise at certain periods, such as during calving.
We have developed a new parameter to identify transient noise peaks that cannot be explained by sound levels predicted based on wind speed (the wind generates waves that dominate the natural underwater soundscape). We found that periods of higher excess noise (likely due to a ship passing nearby) were associated with a decrease in the detection rate of harbour porpoises. This research is currently under peer review for publication.
We have also provided information material on harbour porpoises to WWF Sweden, and input into the production of a video on the Baltic Proper harbour porpoise population, and the threats it is facing.