2007 Special UK Prize Winner ($5,000)

The Passive Porpoise Deterrent - Aquatec Group Ltd., UK

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AQUAmark 100 pinger acoustic porpoise deterrent.
© Aquatec Group Ltd

DESIGN OF THE PASSIVE PORPOISE DETERRENT

At risk of becoming "incidental catch," harbor porpoises and other marine mammals are threatened by gill nets and other fishing gear that often extends over many miles.

Since the 1990s, acoustic pingers have been effective in reducing porpoise bycatch. However, their relatively high cost has hindered implementation, as have concerns over whether they cause noise pollution.

The winning design combines passive acoustic reflectors with a small number of active pingers. The reflectors are fitted into the fishing net every five meters.

When an echolocating porpoise emits a click, the reflectors transmit back a stronger echo, making the reflectors appear to the porpoise to be much larger objects than they are.

The reflectors alone can reduce bycatch, but they are more effective when used in combination with a small number of pingers. The Passive Porpoise Deterrent includes pingers because porpoises do not echolocate all the time.

They sometimes use their optical vision to detect fish; they sometimes simply run silent. Therefore, a reduced number of pingers are used in combination with the reflectors to stimulate porpoise clicks and alert them to danger.

Passive acoustic reflection to reduce bycatch is not new, but past designs have been largely unsuccessful in making the net visible to porpoises. Our proposed technology uses passive devices with a size of several acoustic wavelengths at dolphin sonar frequencies, making the reflector appear acoustically larger than the largest prey. Because the design is cost-effective and simple to maintain it may be easily implemented by fishing communities across the world, resulting in a significant reduction of harbor porpoise bycatch in areas where deterrent or detection devices had been limited in availability or use.

Andy Smerdon, founder, Aquatec Group Ltd

Fishermen pulling up nets, Mafia Island, Tanzania

Andy Smerdon, founder of Aquatec Group Ltd., and Elliot Morley, UK Environment Minister, 2004, discussing pinger technology.

Andy Smerdon (right), founder of Aquatec Group Ltd., and Elliot Morley (left), UK Environment Minister, 2004, discussing pinger technology.
© Aquatec Group Ltd.

TESTING OF THE PASSIVE PORPOISE DETERRENT

Initial tests of the technology were tried on bottlenose dolphins in an effort to keep them from becoming bycatch in drift nets. But work on this ceased when drift netting was banned worldwide. However, the increasing struggle of fisherman to purchase, use and maintain the pingers, in addition to the success from the early tests, revived Aquatec's interest in developing this innovative idea.

THE WINNER

Andy Smerdon graduated in Electronic Engineering from Birmingham University, UK, in 1984 and six years later formed Aquatec Group Ltd. The company designs and develops underwater acoustic and nonacoustic instrumentation that is used by oceanographers and marine scientists around the world.

In 1998, Smerdon met with the late David Goodson of Loughborough University, UK, and the idea of the pingers was inspired and developed. Patented as the AQUAmark 100, their device became the leading pinger used for porpoise bycatch reduction in Europe.

At the same time, Goodson was very enthusiastic about the use of passive reflective devices to enhance net visibility, which he believed could provide an alternative solution for fisheries in developing countries.

Since 1998 Aquatec has developed a range of devices for both detecting and deterring marine mammals. The company has participated in international research projects for the development and improvement of bycatch reduction in commercial fisheries.