Acoustic harassment and acoustic deterrents are technologies used to keep animalsEncyclopedia of Marine Mammals edited by William F. Perrin, Bernd Wursig, J. G.M. Thewissen
page 442 and in some cases humans away from an area. Applications of the technology are used to keep

marine mammal Marine mammals are mammals that rely on marine ecosystems for their existence. They include animals such as cetaceans, pinnipeds, sirenians, sea otters and polar bears. They are an informal group, unified only by their reliance on marine enviro ...

s away from

aquaculture Aquaculture (less commonly spelled aquiculture), also known as aquafarming, is the controlled cultivation ("farming") of aquatic organisms such as fish, crustaceans, mollusks, algae and other organisms of value such as aquatic plants (e.g. Nelu ...

facilities and to keep birds away from certain areas (for instance in the vicinity of airports and blueberry fields). The devices have also been employed to keep marine mammals away from fishing nets. The devices are known as acoustic harassment devices (AHDs) and acoustic deterrent devices, which are smaller AHDsResponsible Marine Aquaculture
edited by Robert R. Stickney and James P. McVey or intended as an awareness tool to warn species to the presence of danger rather than as a tool of harassment at a much louder level. While they have proven effective over the short-term, animals tend to become conditioned over time and can even be drawn to the sounds once they habituate to the lack of real danger and the presence of sustenance. Only acoustic harassment devices that cause actual pain have been found to be effective over the longer term.Conflicts Between Protected Species and Fisheries: Social Science Research and Policy Approaches
Riku Varjopuro, Nordic Council of Ministers, 2003 - Ecosystem management The devices can cause hearing damage in non-targeted species and design changes in the fishing gear, fishing methods, and fish farm design to provide a permanent solution are preferable.

History

Primitive harassment methods included firecrackers, rubber bullets, chasing animals by boat, banging pipes and seal bombs (incendiary devices). Devices emitting loud noises have also been used, including broadcasts of killer whale sounds, pingers, and acoustic buzzers. These often employ shrill sounding screams broadcast between 12 and 17 kHz. Acoustic deterrent devices normally broadcast near 10 kHz and use high volume. The intensity level of acoustic harassment devices has been measured up to 194 dB re 1uPa @ 1 m and the noise can be audible up to 50 kilometers away.

Assessments

Studies of long-term effects on the marine environment have not been carried out, including damage to non-targeted species. Results of the devices are mixed, and they have proved ineffective in some circumstances, especially over the long term, while design improvements such as electric fences to keep seals from climbing into enclosures, gear modification to exclude certain species, and keeping aquaculture plants clean of dead fish have often been effective at solving the problem of keeping predatory species away. Reports indicate that in contrast to the harassment devices, the deterrent devices have been very effective in dealing with

cetacean bycatch Cetacean bycatch (or cetacean by-catch) is the accidental capture of non-target cetaceans such as dolphins, porpoises, and whales by commercial fisheries.Alverson et al. (1994) Bycatch can be caused by entanglement in fishing nets and lines, or ...

. Recent research shows that acoustic deterrent devices intended to scare off seals do not work, but they do scare off porpoises. A new technique called "startle technology" is currently in development. Preliminary trials conducted by the University of St. Andrews shows great promise as a substitute for ADDs.Evaluating and Assessing the Relative Effectiveness of Acoustic Deterrent Devices and other Non-Lethal Measures on Marine Mammals (2014) (http://www.gov.scot/Publications/2014/10/8271/8)

Acoustic devices and acoustic weapon use on humans

Acoustic devices have been used for military purposes including to stress enemies, as an aid in interrogation, and to create "an infrasonic sound barrier". The British Army used "Squawk Boxes" to emit ultrasonic frequencies causing various discomforts.Bad Vibrations: The History of the Idea of Music as a Cause of Disease
by Dr James Kennawa Audio harassment was also used by the U.S. military in the

Vietnam War The Vietnam War (1 November 1955 – 30 April 1975) was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam (Democratic Republic of Vietnam) and South Vietnam (Republic of Vietnam) and their allies. North Vietnam w ...

and was famously depicted in the fictional movie ''

Apocalypse Now ''Apocalypse Now'' is a 1979 American psychological epic war film produced and directed by Francis Ford Coppola. The screenplay, co-written by Coppola, John Milius, and Michael Herr, is loosely inspired by the 1899 novella '' Heart of Darkn ...

'' as helicopters descend on the enemy with loud speakers.

Operation Wandering Soul Operation Wandering Soul was a propaganda campaign and psychological warfare effort exercised by U.S. forces during the Vietnam War. It was an attempt to increase desertions and defections from Việt Cộng forces and weaken their morale. It ...

broadcast voices purported to be dead

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. Other examples include the 350

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HPS-1 Sound System that could be heard 2.5 miles away and was used on the

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Panama Panama, officially the Republic of Panama, is a country in Latin America at the southern end of Central America, bordering South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and ...

where ousted president

Manuel Noriega Manuel Antonio Noriega Moreno ( , ; February 11, 1934 – May 29, 2017) was a Panamanian dictator and military officer who was the ''de facto'' List of heads of state of Panama, ruler of Panama from 1983 to 1989. He never officially serv ...

was in refuge. At the Branch Davidian siege in

Waco, Texas Waco ( ) is a city in and the county seat of McLennan County, Texas, United States. It is situated along the Brazos River and Interstate 35, I-35, halfway between Dallas and Austin, Texas, Austin. The city had a U.S. census estimated 2024 popul ...

, loud music was broadcast. Devices utilising the deterioration of hearing with age have been deployed to drive younger people away, e.g.

The Mosquito The Mosquito or Mosquito alarm is a machine used to deter loitering by emitting sound at high frequency. In some versions, it is intentionally tuned to be heard primarily by younger people. Nicknamed "Mosquito" for the buzzing sound it play ...

References

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History

Assessments

Acoustic devices and acoustic weapon use on humans

See also

References

Further reading