MMO and PAM personnel can help mitigate noise produced during offshore energy industry activities. Oil and gas, offshore wind, tidal energy, subsea cables, and decommissioning operations generate underwater noise can have a significant impact on marine mammals and their marine environments. Protection measures should be top of the agenda when planning offshore operations.
Over the last few decades the effects of human-generated noise on marine mammals has become an increasing concern. We know that underwater sound can affect the health and behaviour of marine animals, damaging hearing, and upsetting their ability to use sound for communication, orientation, and foraging (The Journal of the Acoustical Society of America, 2015), and the North Sea is an area of intense activity for the energy industries. With continuing development of oil and gas resources alongside an upsurge in construction of offshore wind farms, installation of tidal energy devices, harbour redevelopments, and a growing oil and gas decommissioning sector, the potential for human-generated underwater sound is greater than ever.
Studies show that many marine mammals are sensitive to sound
Underwater noise can travel long distances, affecting large areas, and imposing a range of negative effects both physical and behavioural. In the UK marine mammals are protected by law under the UK Wildlife & Countryside Act (1981), in addition to other agreements, rules and statutes such as the Agreement on the Conservation of Small Cetaceans in the Baltic & North Seas (ASCOBANS) (1992), European Habitats & Species Directive (1992), Offshore Petroleum Activities (Conservation of Habitats) Amendment Regulations (2007), Conservation of Offshore Marine Habitats and Species Regulations (2017), and Conservation of Habitats & Species Regulations (2017). Geophysical surveys in particular have the potential to result in a deliberate injury or disturbance offence as defined under UK regulations to European Protected Species (EPS).
For this reason, operators have be proactive in their attempts to mitigate the effects of sounds being generated during industrial activities, as there is a real potential for harm whether through disruption to the marine environment, or auditory injury to marine animals. Pile-driving, for example, used in offshore windfarm construction is a significant source of underwater noise. Pile-driving noises during wind turbine installation in deep-water off North East Scotland, at the Moray Firth Special Area of Conservation (SAC), were measured against noise exposure criteria for marine mammals to assess possible effects on a protected population of bottlenose dolphins. Findings showed that potential behavioural disturbance could occur within a 50 km range. (Marine Pollution Bulletin, Volume 60, Issue 6, June 2010).
JNCC guidelines recommend the use of Marine Mammal Observers (MMOs) and Passive Acoustic Monitoring (PAM) operators to detect marine mammals. There should be a delay in operations if a marine mammal is detected within a specified mitigation zone
The effects of seismic operations are well recognised for their harmful effect on marine animals and regulations are in place to reduce the risk of deliberate injury. The Joint Nature Conservation Committee (JNCC) has developed mitigation guidelines, written primarily for the oil and gas industry but adopted by other industries using geophysical technology in the marine environment. This forms part of the consent for geophysical activities within the United Kingdom Continental Shelf (UKCS). These guidelines recommend the use of Marine Mammal Observers (MMOs) and Passive Acoustic Monitoring (PAM) operators to detect marine mammals, with a delay in operations should a marine mammal be detected within a specified mitigation zone. MMOs receive formal training via a JNCC approved course, and discussions are currently underway to identify minimum standards for PAM.
The role of the MMO is to be present during offshore operations to identify and help monitor marine mammals during daylight hours, while additional acoustic (PAM) monitoring increases the likelihood of detection where visual monitoring is not possible
MMO’s provide advice to ensure that operations comply with relevant guidelines and work to reduce the risk of injury or disturbance to marine mammals during operations. Should marine mammals enter an exclusion zone prior to, or during operations the on-board MMO will advise that operations be shut down until the animals are at a safe distance. MMO’s are commonly employed during seismic surveys, where blasts of compressed air are used to produce acoustic energy to help identify potential oil and gas reserves beneath the seabed, and during offshore construction projects such as wind farms where windfarm piles are driven into the seabed using steam or hydraulic powered hammers. The on-board MMO will visually detect and identify marine mammals, and accurately assess their range and movements. Visual monitoring si conducted using the highest platform with the best all-round visibility. Visual observation is carried out using pair of binoculars, and is done in all marine mammal observation work. Extensive knowledge of the area along with an understanding of oil and gas operational procedures aids the MMO in working offshore with the client team.