IWDG Consulting have just successfully recovered the first SAM deployment at two proposed offshore windfarms in the Irish and Celtic Seas. Static Acoustic Monitoring (SAM) is a method of gaining fine scale data on occurrence and habitat use by odontocetes, especially harbour porpoise which can be difficult to survey visually.
SAM can be a challenging techniques especially off Ireland’s east coast as tides are very strong and techniques to deploy, and recovery are paramount. Through working with fishers who are skilled at these techniques at sea, IWDG Consulting trialled a new system over the last few months which, with some tweaking, proved very successful.
Dr Simon Berrow CEO of the IWDG said “this is very encouraging, given the requirements for offshore wind to obtain acoustic data, not only from dolphins and porpoises but to record ambient noise. If these wind turbines will be operating in a naturally noisy environment caused by strong tides and movement of benthic substrates, the impact of increased noise levels associated with turbine operation will be less than in a quieter environment.”.
This is the the third SAM contract IWDG Consulting have won from the offshore wind industry. The IWDG have recommended that SAM should be collected as part of site investigations to identify and avoid important foraging areas, and to be used two years prior to construction starting and during operation to ensure any displacement that may occur is temporary and activity returns to at least its pre-construction levels, or possibly increase through artificial reef effects.
Recent studies using SAM has shown that bottlenose dolphins and harbour porpoises were not excluded from sites in the vicinity of impact piling or vibration piling; nevertheless, some small effects were detected. Bottlenose dolphins spent a reduced period of time in the vicinity of construction works during both impact and vibration piling. The probability of occurrence of both cetacean species was also slightly less during periods of vibration piling (https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.1793).
Recently a study showed that wind turbine installation using gravity-base foundations had no long-term effects on the occurrence of dolphins or porpoise and may represent an offshore construction methodology that is less impactful to dolphins and harbour porpoise than impact pile-driven turbine installation methods (https://link.springer.com/article/10.1007/s00227-023-04240-1).
IWDG is committed to working with the offshore wind companies to not only ensure impacts from the rollout of offshore wind is minimal but all the opportunities to enhance biodiversity and support restoration projects is fully exploited.