How an underwater noisemaker protects dolphins in Asia

Irrawaddy river dolphin in Cambodia

For the critically endangered Irrawaddy dolphin, fishing gear is a deadly threat. In Indonesia’s Mahakam River, two-thirds of dolphin deaths in the past 25 years were drownings caused by entanglement in fishing nets. Now a relatively inexpensive electronic device known as a “pinger” shows promise for preventing dolphins from becoming entrapped. These underwater noisemakers have been used to protect various marine life, but this is the first time they’ve been proven effective at safeguarding freshwater dolphins.

How it works

The small acoustic device, about the size of a banana, is attached to a gillnet and emits a pulsing noise that annoys the dolphins but doesn’t harm them. Dolphins steer clear of the nets, deterred from trying to snatch fish from them, and can therefore feed and swim more safely in their habitat. Fishers’ nets, meanwhile, sustain less damage.

Yellow pinger device on rope© RICHARD BORNEMANN/WWF-US
Man in canoe holds pinger device attached to net© YK-RASI

A win-win

Pingers benefit both dolphins and fishers’ livelihoods. A six-month study led by conservation organization Yayasan Konservasi RASI and supported by WWF recently revealed that fishers who used the devices saw a 40% increase in their daily catch—an additional 350 to 500 pounds of fish—and tended to catch larger fish, increasing their profits.


Approximate number of Irrawaddy dolphins that live in the Mahakam River. Small populations are also found in the Mekong and Ayeyarwady rivers, where, in addition to entanglement, they’re impacted by habitat degradation, unsustainable fishing practices, and water pollution.


Reduction in dolphin bycatch during the study—and the percentage of participating fishers who kept using the devices after the trial ended.

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