In an Opinion dated 15 July 2016 in the case of Natural Resources Defense Council et al v Penny Pritzker et al, issued by the United States Court of Appeals for the Ninth Circuit (a US Federal appellate Court covering California and other western US states), Circuit Judge Ronald M. Gould has held that the US Navy’s peacetime use of Surveillance Towed Array Sensor System Low Frequency Active Sonar (which emits powerful, low-frequency sonar pings) is inconsistent with US federal law obligations under the Marine Mammal Protection Act, including, in particular, the mitigation measures required to protect marine mammals such as whales, dolphins, and walruses.
As the Judge put it, “Whales, dolphins, walruses, and other marine mammals rely on perceptions of underwater sound for vital biological functions such as catching prey, navigating, and communicating. The United States Navy operates LFA sonar vessels around the world for another vital purpose: to protect the USA from increasingly quiet foreign submarines. The US Navy has determined that LFA sonar is the most effective way to detect potentially hostile submarines. LFA sonar uses a set of transmitting projectors that are suspended by a cable from an ocean surveillance ship. The projectors produce low-frequency sound pulses at an intensity of approximately 215 decibels (dB), in sequences that last 60 seconds on average. LFA sonar can detect enemy ships day and night in varied weather conditions over hundreds of miles. LFA sonar, while beneficial to US national defense, can harm many marine mammal species, particularly “low-frequency hearing specialists” such as baleen whales, but also sperm whales and pinnipeds such as seals and walruses. LFA sonar disrupts the hearing of these animals and can cause physical injury at sound levels greater than 180 dB. Effects from exposures below 180 dB can cause short-term disruption or abandonment of natural behavior patterns. These behavioral disruptions can cause affected marine mammals to stop communicating with each other, to flee or avoid an ensonified area, to cease foraging for food, to separate from their calves, and to interrupt mating. LFA sonar can also cause heightened stress responses from marine mammals. Such behavioral disruptions can force marine mammals to make trade-offs like delaying migration, delaying reproduction, reducing growth, or migrating with reduced energy reserves.”
The Court held that the US Navy’s preferred mitigation measures were inadequate, for the purposes of the Marine Mammal Protection Act. The Court found that the US National Marine Fisheries Service had failed to adopt reasonable safeguards recommended by the government’s own scientists to reduce or prevent harm from the sonar system, resulting in a “systematic underprotection of marine mammals” throughout “most of the oceans of the world.” Experts had recommended that the Fisheries Service protect the Galapagos Islands off the coast of Ecuador, the Papahanaumokuakea Marine National Monument off Hawaii, Challenger Bank off Bermuda, and other areas around the world important to whales, dolphins, seals, and other marine mammals.
For more information, see: