Sounds for seals

摘要

Acoustic technology that could more effectively protect marine installations from unwanted sea life has been unveiled at St Andrews University. The system could be used to keep dolphins away during turbine installation offshore or to protect fish farms from seals - a major problem for the seafood industry. Group leader Vincent Janik, a specialist in communication in marine mammals, said his team has found the optimum target-specific signals to irritate sea mammals just like 'nails on a chalkboard' can grate on a person's nerves.rnThe sound can be produced by an underwater transducer attached to a fish farm cage submerged 4m-5m in the water. The battery of the transducer control unit would need to be changed every few days. Janik said the kit would include a detection system that would trigger the sound only when a marine mammal approaches. He said there are two possible methods that could be used for the initial detection of nearby sea mammals. One is an active method such as sonar, where a distinctive 'ping' is transmitted and an echo is then listened for. The other is a passive method, such as acoustic daylight imaging technology, which uses the ambient noise in the ocean to create an image. Janik said with that technology an underwater dish would reflect the acoustics collected from the surrounding ocean area back to a series of underwater microphones facing inward on the front of the dish. The microphones would convert the acoustic image into a set of electrical signals that could be used to alert the deterrence system of a new object in the area.