TAIPEI (Taiwan News) — A new handbook was released about the impact of underwater noise on cetaceans and the marine environment.
National Sun Yat-sen University (NSYSU) researchers Chan Hsiang-chih (湛翔智) and Wei Rui-chang (魏瑞昌) conducted underwater noise assessments through underwater sensors and data buoys.
Wei said that when people talk about environmental pollution, noise issues do not get enough attention, per an NSYSU press release. For example, he said that dirty river water, coral reef bleaching, and garbage strewn on beaches have an immediate visual impact, which easily attracts attention.
NSYSU’s Institute of Undersea Technology began pursuing this subject in 1998. After the major population decline of the Taiwanese Indo-Pacific humpback dolphin, the issue entered public view.
Wei said cetaceans are the top predators in the marine food chain, and they play an important role in the marine ecosystem.
Impact of ships and wind turbines on marine life. (National Sun Yat-sen University image)
Dolphins and whales typically rely on hearing and vocalizations to communicate, which enables them to socialize and reproduce. Long-term disturbance by underwater noise may lead to physiological stress, including hearing loss and a change of habitat.
In severe cases, it may cause damage to the hearing of cetaceans, leading to beach stranding or death. To conserve the cetacean population, accurate underwater noise monitoring and assessment tools are needed.
Closer monitoring of the ecological habits of cetaceans and their responses to underwater noise could minimize the impact of underwater noise on cetacean populations. It could also lead authorities to become more proactive in measuring and mitigating the impact of noise on cetacean populations.
Chan said he began studying underwater noise 25 years ago and has investigated data, such as passing ships along with wind and waves. He has also participated in Taiwan-U.S. cooperative experiments.
Chan said that Taiwan has been paying attention to the prevention and control of underwater noise since 2012. It took him more than two years to co-author the handbook.
He said the first half is dedicated to a scientific survey on cetacean ecology. The second half is an assessment and contains preventive methods to reduce underwater noise over the past decade.
He analyzed data in environmental impact assessment reports associated with offshore wind farm development. However, he said most assessments rarely investigate or extrapolate information from the data, such as the cumulative impact on aquatic creatures.
Wei said offshore wind farms have contributed to underwater noise, but the main source continues to be passing ships. Due to increased economic activity, ship noise is on the rise each year.
Surveys showed that the ocean soundscape has been seriously disturbed by human beings. In addition to cetaceans, other marine life such as fish, shrimp, sea turtles, and cetaceans have been disturbed by underwater noise.
Furthermore, whales and dolphins who inhabit offshore waters may be the first to be affected by increasing underwater noise. A reduction in their species will indicate offshore ecology is severely threatened and may never recover.