Noise in the ocean

Harbour porpoises (Phocoena phocoena) off the North Sea coast. © OSC 2012.

Harbour porpoises (Phocoena phocoena) off the North Sea coast. © OSC 2012.

The use of the ocean seabed as a natural resource is increasing world-wide. As a result, there has been an increase in the scale of offshore activities such as seismic exploration, exploration drilling, oil and gas production, pipeline activities and electromagnetic (EM) surveys. The majority of these offshore man-made (anthropogenic) activities create underwater noise which has the potential to disturb marine mammals such as whales, dolphins, porpoises (collectively known as cetaceans) and seals (pinnipeds) either directly or indirectly, for example, by disturbance of their prey.

In recent years, industry regulators, offshore industries and the scientific community have become concerned about the effects of anthropogenic sound (in particular low-frequency sound) on marine mammals. In 1994, the National Research Council (NRC) issued a report titled “Low frequency sound and research needs” which concluded that: (1) very little is known about the effects of low frequency sound on marine mammals, and (2) it is difficult to establish regulatory policy in the absence of data.

Passive Acoustic Monitoring (PAM)

“A proper PAM system is only of use for marine mammal mitigation purposes if operated by a qualified and experienced PAM operator with a proven track-record of bioacoustic signal detection and analysis”.

Dr. Victoria Todd (OSC Managing Director).

Passive Acoustic Monitoring (www.passiveacousticmonitoring.co.uk) involves listening passively for cetacean vocalisations with a calibrated underwater microphone (hydrophone), in many cases to gauge direction and distance of vocalising animals. Passive Acoustic Monitoring systems comprise specialist hydrophones manufactured to target cetacean vocalisations of interest, signal processing units (incorporating apposite sound card technology for sampling relevant cetacean frequencies) and sophisticated marine mammal detection software such as PAMGuard (www.pamguard.org), for which OSC is a beta testing partner.

Passive Acoustic Monitoring systems are becoming increasingly important monitoring tools for mitigating the effects of underwater industrial noise on marine mammals (and other wildlife). In many cases, Passive Acoustic Monitoring is a permit requirement for offshore activities, particularly in sensitive areas. World-wide mitigation guidelines are being revised and updated continually (see www.marinemammalmitigation.co.uk) and it is anticipated that Passive Acoustic Monitoring will become a universal legal requirement in the near future.

Reducing your operational downtime

An advantage to Passive Acoustic Monitoring is that it can be used at night and in poor visibility/weather conditions. In many cases, Passive Acoustic Monitoring is used to permit night-time start-up procedures, when Marine Mammal Observers (MMOs) are unable to see; however, it is not recommended that PAM be used in isolation for a plethora of reasons, including the fact that cetaceans do not always make noise. Passive Acoustic Monitoring is thus used mainly in conjunction with Marine Mammal Observers (www.marinemammalobserver.co.uk).

Ocean Science Consulting’s equipment is 100% fully-redundant and our staff have years of MMO and PAM experience, so are able to make split-minute in-the-field decisions regarding what is and what is not permissible within permit guidelines. This reduces operational downtime and meets industry deadlines. In this industry, it pays to use only the best personnel; inexperienced and underqualified operators make mistakes that can cost clients’ money and jeopardise mitigation. By using employees, rather than subcontractors, we raise the standard. When demand exceeds supply, however, we subcontract from our extensive pool of reliable and tested operators.

OSC Passive Acoustic Monitoring Systems

Ocean Science Consulting offers a comprehensive service from beginning to end. We undertake Marine Mammal Mitigation Plans (MMMPs) where we assess the range of impacts on marine mammals associated with seismic/drilling/etc. survey activities, and identify steps in order to avoid, remedy or mitigate negative effects and co-ordinate research activities.

We have a choice of Passive Acoustic Monitoring systems to suit specific objectives and budgets. As well as providing qualified and experienced Marine Mammal Observers (www.marinemammalobserver.co.uk), we provide towed arrays, static systems and dunking elements; however, in-line with our extensive field experience, we only provide our equipment together with our Passive Acoustic Monitoring Operators. See www.osc.co.uk for more information about our different services.

OSC towed hydrophone arrays

OSC PAM system on seismic vessel winch. © OSC 2012.

OSC PAM system on seismic vessel winch. © OSC 2012.

Our towed arrays are deployed behind a vessel and are used for surveying large areas. Towed arrays are ideal for mobile surveys, such as, seismic, dredging, pipe and cable-laying, bathymetric, etc. We offer two options for towed arrays: ‘new generation’ OSC systems and commercial systems. Through our own research and development our ‘new generation’ OSC systems are optimised to detect cetacean vocalisations between both extremes of the sound spectrum and designed to meet the expectations of science, industry and its regulators. Our commercial systems are designed to meet the needs of the seismic survey industry with duplicated contingency units and robust construction. For offshore surveys the client is required to supply a vessel to deploy and tow the hydrophone array. For inshore surveys OSC can provide our own dedicated category 3 – up to 20 miles from a safe haven – research vessel (R/V Porpoise) capable of deploying and towing the hydrophone array. R/V Porpoise can be towed to anywhere within Europe and is located at the head offices’ warehouse in Dunbar, Scotland.

OSC click detectors

We have a range of different cetacean click detectors, but are peer-reviewed published experts in the use of T-PODs (www.t-pod.co.uk) and C-PODs (www.cpodclickdetector.com). PODs are static Passive Acoustic Monitoring systems used to detect echolocation click trains of toothed whales, dolphins and porpoises (collectively known as odontocetes). These Passive Acoustic Monitoring systems are relatively low-cost and fully-automated, providing a cost effective and low-effort way to gather large datasets over short or long periods of time. T-PODs and C-PODs are not used for real-time mitigation. T-PODs and C-PODs are effective Passive Acoustic Monitoring systems used for conducting Environmental Impact Assessments (EIAs), investigating odontocete interactions with offshore installations, fisheries, acquiring acoustic behavioural patterns, habitat use, small population trends and many others.

OSC Passive Acoustic Monitoring operators

Passive Acoustic Monitoring operators from OSC hold full up-to-date offshore certifications and medicals. Our PAM operators are full-time employees, qualified degree-level scientists and have undergone extensive OSC training. Our PAM operators have 24/7 access to shore-based technical support, which can be mobilised at very short notice if needed. Our Passive Acoustic Monitoring systems, PAM operators and Marine Mammal Observers comply with International Association of Geophysical Contractors (IAGG) and Oil & Gas United Kingdom (OGUK) guidelines.

Company Experience

We are a Scottish-based company with a world-wide punch. Incorporated (and trading) since 2004, our company focuses entirely on marine mammal risk mitigation. Our success is based around the fact that our core scientific and technical staff are able to translate the needs of both the manufactured and natural environments into workable solutions for the problems facing industry today. This gives our clients the benefit of environmental consultancy services that comprehend the economic need for future development.

Throughout the economic downturn, our enthusiastic and committed staff have maintained a vibrant consultancy at the leading edge of environmental change. This is reflected in the fact that ca. 60% of our contracts are generated from repeat client work; new contracts are usually by word-of-mouth recommendation, and all our staff can provide glowing industry references. A list of clients can be viewed at www.osc.co.uk.

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