Hong Kong researchers are set to rock the boats of fishermen who use dynamite to catch fish, with an underwater microphone that can point law enforcers in the direction of the bombers. The so-called 'hydrophone' has been developed by researchers at the Hong Kong University of Science and Technology and successfully tested in waters off Kota Kinabalu in Malaysia, Agence France-Presse reported last week. George Woodman, team leader and head of science at Li Po Chun United World College, said the project was eight years in the making. His interest had been sparked by an incident in 1994, in which he and a friend were within close range of a fisherman using explosives to stun fish. 'I was diving with a friend involved in a reef survey in Malaysia in 1994 when we heard a blast and got shaken around,' he said. The practice is illegal, but employed in both small-scale and industrial fishing operations in many parts of Indonesia, Malaysia, Vietnam and elsewhere in Southeast Asia. 'The scale of the problem is not that well known, but using explosives for fishing is very damaging,' Dr Woodman said. 'One or two bombs won't do much, but repeated bombing destroys the structure of a coral reef.' The newly developed hydrophone, which Dr Woodman described as a distant 'cousin' of technology previously employed by the military, can detect the sound of a blast underwater and point to its source, making the task of law enforcers much easier. Authorities have been using similar but less advanced technology to try to detect dynamite fishing. But unlike the new system, which uses computer technology to 'tune in' to the sound of the blast, the old underwater microphones were unable to distinguish between bomb blasts and other marine noise. 'It's actually quite noisy down there [underwater],' Dr Woodman said. 'In our early research, we used the old microphones and heard many bomb-like sounds. We thought we'd discovered a large number of bombs but found that the sounds were actually coming from these so-called pistol shrimps.' Dr Woodman and his team, comprising Simon Wilson, Reinhard Renneberg, Vincent Li and Paul Harrison, used software to develop a system that could distinguish the sounds. 'We have proved it works and have got results. The next step is to trial it at a number of other locations, including Hong Kong,' Dr Woodman said. He said the team hoped to develop a 'series of products' and was keen to secure financial support. 'We'd like to get the cost down as low as possible, say to between US$5,000 (HK$39,000) and US$15,000, but that is still a long way in the future.' The researchers are aleady in discussion with the Agriculture, Fisheries and Conservation Department. The hydrophone could have a range of applications, even if law-enforcement agencies were unable to reach the detected source of a blast in time to catch the culprit. 'At least governments would be able to get a handle on how much bombing occurs and track the trends,' Dr Woodman said.