Sonar devices have been installed at Elizabeth Quay to keep dolphins away from construction

Posted November 15, 2013 16:28:21

Sonar devices have been installed at the Elizabeth Quay construction site after dolphins repeatedly become trapped inside a barrier.

On three occasions dolphins have swum inside a silk curtain on the Swan River designed to contain sediment.

To stop that happening again, the Metropolitan Redevelopment Authority has installed 15 devices known as 'pingers'.

MRA chief executive Kieran Kinsella said the devices were commonly used by fisherman to discourage dolphins from entering their nets.

"It's a sonar device that emits a warning signal at a frequency that the dolphins can hear, humans can't hear that frequency, and that basically warns the dolphins to stay away.

When the dolphins become trapped, work at the site must be stopped and MRA Chief Executive Kieran Kinsella hopes the pingers will protect the animals and prevent further disruptions.

"Overall we don't expect that we'll lose any working time from it, it's just that we've had to reorganise our schedule," he said.

The MRA said despite several inspections it still does not know how the dolphins got around the curtain in the first place.

Topics: mammals, perth-6000