Sound Effects: Protecting Marine Mammals Using Acoustic Technology
Oct 17, 2011
In November 2009, RESOLVE facilitated a workshop in Boston, MA on the “Status and Applications of Acoustic Mitigation and Monitoring Systems for Marine Mammals.” The workshop was convened by the Bureau of Ocean Energy Management, Regulation and Enforcement, and the 200 participants explored the capabilities and limitations of using passive and active acoustic systems to monitor and help mitigate adverse impacts of marine mammals in offshore environments.
Why was the issue of acoustic technology so important for an agency that focuses on offshore energy? The answer is not readily apparent unless one knows something about sound in water, and how it interacts with marine animals and ecosystems.
Have you ever dunked your head underneath the water at the swimming pool and just listened? Sound behaves so differently under water than in the air. It conducts better, and travels longer distances at a faster speed (particularly in seawater). While underwater sounds may be strange and unintelligible to our human ears an entire order of marine mammals, the cetaceans (whales, dolphins, and porpoises), have evolved to use underwater sounds through echolocation to learn information about their surroundings and communicate with others in their species.
Now imagine humans coming along and changing the marine acoustic environment through noise created near the water, on the water, and in the water. Anthropogenic sound can greatly affect these animals directly (through physical harm) and indirectly (by impacting their ability to echolocate and communicate). Some of the most extreme examples of this are beached whales after sonar tests.
Americans decided back in 1972, with the passage of the Marine Mammal Protection Act (MMPA), that these animals should be protected. The MMPA prohibits the “take” of marine mammals. Specifically, we cannot “harass, hunt, capture, kill or collect, or attempt to harass, hunt, capture, kill or collect” marine mammals. The Bureau of Ocean Energy, Management, Regulation and Enforcement (BOEMRE) is given the task of protecting these animals while managing offshore energy development activities, which can create large-scale sound events. These events can result in the take of a whale or other marine mammal if within a certain distance of the sound. Examples of these events include survey companies using seismic blasts to locate offshore petroleum deposits and offshore wind turbine developers using pile driving to provide foundation support for the turbines.
BOEMRE has long required that those carrying out such offshore activities visually monitor for marine mammals and to stop work if an animal is spotted. But acoustic technology can complement and enhance visual monitoring and help ensure there are no marine mammals nearby at the time of a seismic blast or pile driving. To determine this technology’s capabilities and limitations, BOEMRE partnered with RESOLVE to hold the November 2009 workshop, which was attended by 200 regulators, researchers, operators, and conservationists from all over the globe to discuss how acoustic technology can monitor and help mitigate adverse impacts to marine mammals.