Dear MARMAM colleagues, On behalf of my co-authors I would like to share our recent publication in Marine Pollution Bulletin: Fernandez-Betelu, O., Graham, I.M., Malcher, F., Webster, E., Cheong, S.H., Wang, L., Iorio-Merlo, V., Robinson, S. and Thompson, P.M., 2024. Characterising underwater noise and changes in harbour porpoise behaviour during the decommissioning of an oil and gas platform. Marine Pollution Bulletin, 200, p.116083. Link to paper (open access): *https://www.sciencedirect.com/science/article/pii/S0025326X24000602 <https://www.sciencedirect.com/science/article/pii/S0025326X24000602>* Abstract Many man-made marine structures (MMS) will have to be decommissioned in the coming decades. While studies on the impacts of construction of MMS on marine mammals exist, no research has been done on the effects of their decommissioning. The complete removal of an oil and gas platform in Scotland in 2021 provided an opportunity to investigate the response of harbour porpoises to decommissioning. Arrays of broadband noise recorders and echolocation detectors were used to describe noise characteristics produced by decommissioning activities and assess porpoise behaviour. During decommissioning, sound pressure spectral density levels in the frequency range 100 Hz to 48 kHz were 30–40 dB higher than baseline, with vessel presence being the main source of noise. The study detected small-scale (< 2 km) and short-term porpoise displacement during decommissioning, with porpoise occurrence increasing immediately after this. These findings can inform the consenting process for future decommissioning projects. Please, do not hesitate to contact me should you have any questions regarding our work (oihane.fernandez@abdn.ac.uk). Kind regards, *Dr Oihane Fernandez-Betelu* Research Fellow Lighthouse Field Station, Institute of Biological & Environmental Sciences, University of Aberdeen, Cromarty IV11 8YL.