Passive Acoustic Monitoring (PAM)

Passive Acoustic Monitoring (PAM) in the aquatic environment refers to the use of underwater microphones (hydrophones) to detect, monitor and, in some cases localise, vocalising marine mammals. Passive refers to the fact that we merely listen, and do not put noise into the environment, so this method should not be confused with active acoustic systems, such as Acoustic Deterrent Devices (ADDs, e.g. pingers), Acoustic Harassment Devices (AHDs, e.g. seal scarers), and sonar used for navigational and other purposes.

Underwater sound & marine wildlife

The intense sounds produced during some surveys (e.g. seismic) may potentially have physical, physiological and behavioural effects on underwater life, such as marine mammals (dolphins, porpoises, whales and seals). Contrary to public opinion, the production of man-made (anthropogenic) underwater noise is often regulated heavily with guidelines, such as those provided by Joint Nature Conservation Committee (JNCC). For a review of these guidelines, please refer to

Is Passive Acoustic Monitoring required for my project?

Passive acoustic mitigation is required increasingly as a marine mammal monitoring tool when mitigating against the effects of anthropogenic sound such as seismic airguns, pile-driving, conductor ramming, rig-decommissioning and military sonar. Ocean Science Consulting is first and foremost, a marine consultancy. We review projects at the planning stage and advise on any potential need for Passive Acoustic Monitoring, Marine Mammal Observers etc. We have several types of Passive Acoustic Monitoring System, for which full specifications can be provided upon request. For long-term monitoring of odontocetes (toothed species of dolphin, whale and porpoise) in areas where real-time mitigation is not required (i.e. before, during after an industrial activity), we advise the use of autonomous echolocation click detectors called T-PODs ( and C-PODs. For example, in 2004, we were the first scientists in the world to discover harbour porpoises feeding around drilling rigs, which, with permission from our clients, was published in a peer-reviewed journal (click here for PDF:

For mobile surveys, such as seismic, bathymetric, pipe/cable-laying, dredging etc. or for coverage of larger areas, such as during pile-driving for offshore windfarm installations, we advise the use of our towed Passive Acoustic Monitoring Systems.

OSC Passive Acoustic Monitoring Systems

Ocean Science Consulting leases state-of-the-art static and towed Passive Acoustic Monitoring Systems to some of the largest oil and gas companies in the world (see Our systems are 100% redundant, serviced continually and tested in-house for offshore reliability, offering real-time monitoring using the latest detection software such as PamGuard ( For inshore surveys such as seabed inspections, windfarm installation, dredging, pipeline inspection etc, our systems can be provided with a small research vessel. For offshore surveys, the client is required to supply a vessel capable of deploying and towing our arrays.

Deployment of a Passive Acoustic Monitoring System aboard the PGS Atlantic Explorer. © OSC 2011.

Deployment of a Passive Acoustic Monitoring System aboard the PGS Atlantic Explorer. © OSC 2011.

OSC Passive Acoustic Monitoring Operators

Ocean Science Consulting’s Passive Acoustic Monitoring Operators hold the full complement of offshore certifications and medicals for work world-wide. Both our Passive Acoustic Monitoring Systems and Operators comply with International Association of Geophysical Contractors (IAGC) and Oil & Gas United Kingdom [energy industry] (OGUK) (formerly called United Kingdom Offshore Operators Association, UKOOA) guidelines as and when is necessary.

Ocean Science Consulting’s Passive Acoustic Monitoring Operators hold professional indemnity, public liability and travel and accident insurance and are covered under our extensive employer’s liability policies. Our personnel also receive 24-hour onshore technical support. Our engineers install, fault-find, calibrate, un-install, prepare and pack systems for shipment, and have access to company-owned vans and trucks for delivery and collection of equipment for European contracts. We only provide our Passive Acoustic Monitoring Systems with our own Operators and installation engineers.

Why our Passive Acoustic Monitoring Operators are different

Our Passive Acoustic Monitoring Operators are highly trained degree-level qualified scientists. Most are marine biologists, trained to detect and recognise acoustic signals from marine mammals. The majority of our Passive Acoustic Monitoring Operators are full-time employees that have undertaken Ocean Science Consulting traineeships, including one-to-one tuition, combining both attendance of commercially-run Passive Acoustic Monitoring and Marine Mammal Observer courses, and rigorous in-house training and bench-marking sessions. Unlike many other consultancies that use contract workers exclusively, we subcontract only when all of our full-time Passive Acoustic Monitoring Operators are already in the field. This sets us apart from the competition and is our contribution to improving the standards in the industry.

Ocean Science Consulting’s Operators usually work on back-to-back 12-hour shifts, and often support our Marine Mammal Observers (see All of our Passive Acoustic Monitoring Operators are trained Marine Mammal Observers, which permits role-switching and extra knowledge-based support in the field.

Our promise

Ocean Science Consulting has no affiliation with any commercial entity, Governmental or Non-Governmental Organisations, and is wholly-independent, in order to maintain complete impartiality. This is reflected in our mission statement: “from sound science comes wise decisions. We adhere to strict client confidentiality agreements, and if subcontracted, never approach the main client directly and always report a conflict of interest.

Company experience

We are a Scottish company, securing our first offshore drilling-rig contract in 2004 with Wintershall (, within three days of company incorporation. Since then, we have increased in capacity and capability, and our client list now includes major players such as Shell ( and CGGVeritas ( Our services are regularly praised; hence most of our custom is from repeat clients. A full client list and references are available upon request.

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