In April 2023, MKO started a Marine Mammal Observer (MMO) service offering and completed surveys for Donegal County Council’s maintenance dredging campaign at Buncrana Pier, Co Donegal. These works aimed to allow for the safe and navigable passage of RNLI Lifeboats and other small vessels into Buncrana Pier at all tide stages.
Marine mammals (i.e., whales, dolphins, porpoises, and seals) use sound for important functions that include communication, prey localisation, and navigation. Such reliance on sound has raised concern over the increased underwater anthropogenic noise, which can overlap with marine mammal hearing ranges. This can cause acoustic interference, behavioural responses, stress, and displacement, as well as temporary or permanent hearing loss in marine mammals. Underwater noise is emitted from various coastal works, including dredging and activities such as drilling, pile driving, commercial ship traffic, and geophysical acoustic surveys. Under current legislation, disturbing or injuring a marine mammal in Ireland via introduced anthropogenic noise or other sources is an offence.
For these reasons, a marine mammal observer is required to be present for such works to implement the mitigation measures as outlined in the NPWS guidance document ‘Guidance to Manage the Risk to Marine Mammals from Man-Made Sound Sources in Irish Waters’ (2014). The document contains the MMO survey protocols for the activities mentioned above. According to this guidance, a qualified MMO is defined as ‘a visual observer who has undergone formal marine mammal observation and distance estimation training (JNCC MMO training course or equivalent) and also has a minimum of 6 weeks full-time marine mammal survey experience at sea over a three-year period in European waters.’
The survey guidelines vary depending on the activity taking place (i.e., dredging, drilling, pile driving etc.). However the primary role of the MMO across all activities generally involves carrying out pre-start-up effort watches of 30/60 minutes for marine mammals in suitable conditions within a designated Monitored Zone from the sound source. This occurs prior to the commencement of any noise-producing activity. A delay to operations must be enforced by the MMO in the event of a sighting during a pre-watch. The Monitored Zone and surrounding areas are also surveyed for marine mammals during the operations.
This is to ensure the safeguarding of marine mammals occupying the area.