Wonder Reef acoustic array captures secret underworld of reef and surroundings
Griffith University researchers are studying the underwater sounds of the Gold Coast’s newest diving attraction, the Wonder Reef, and sharing their findings.
In a world first trial on an artificial reef, an acoustic array was deployed at Wonder Reef consisting of a permanent hydrophone (an underwater microphone) capturing whales and dolphin sounds, an acoustic receiver to detect tagged fish and sharks, as well as a live stream hydrophone accessible to the public in real time.
Over the past whale season, humpback whale vocals have been captured providing new insights into the social behaviour of these charismatic animals.
Using an Aural M2 set of hydrophones – worth $17,000 each – Dr Olaf Meynecke has captured over 8,000 files yielding several months of sound. The hydrophone batteries last for about 2-3 months, then they need to be replaced and recharged.
The hydrophone is attached to the bottom of the reef at 27m depth where it can capture sound from the reef itself but also from further away (several kilometres depending on sea conditions).
The range of sound frequencies or waves captured is from 10hz to 16,000hz covering all whale vocals and most of the dolphin clicks.
In addition to the permanent hydrophone there is an acoustic receiver that listens to certain frequencies emitted from acoustic tags that have been previously implanted into fish and sharks. Recently a zebra shark was detected by the receiver. The Zebra shark travelled an astonishing xx along the east coast of Australia all the way to Wonder Reef.
A specially designed live streaming hydrophone, much smaller than its bigger cousin the Aural M2, is sending acoustic waves from the reef for everyone to tune in to. There are many different sounds to capture from whales, dolphins to grunting fish, clicking shrimps, moving chains and different types of boat traffic.
There are many potential research projects that can derive from this in the future studying various aspects of marine mammals (dolphins hunting around the site, whales singing, rays and fish taking residence).
The researchers hope that this initial work will encourage funding for future research projects that can expand on the initial findings. Dr Olaf Meynecke: In partnership with Gold Coast City Council we can provide education, monitoring and attraction for divers for Wonder Reef capturing the acoustic landscape of this unique feature on our Gold Coast.
But there is also a global impact as we are the first to collect this combination of data on an artificial reef. It sheds light on how marine life is utelising a new habitat and provides the public with a unique window to the underwater world. A way forward for community engagement for other places worldwide