Researchers are testing if underwater alarms can reduce the number of migrating Humpback Whales caught in shark nets.
The alarms, known as pingers, emit a low frequency noise that the whales can hear, acting like a sonic warning to avoid the nets designed to protect swimmers.
Taronga Zoo’s Marine Biologist, Dr. David Slip, said: “Each year, particularly during the migration period, Humpback Whales get entangled in shark nets. This usually results in serious injury and sometimes causes the whale’s death.”
“Lots of effort has gone in to using various acoustic devices to deter whales from swimming into the nets, but there’s been little research to see if it’s actually been successful,” said Dr. Slip.
“As the east Australian Humpback Whale population continues to increase, whales are more likely to encounter nets and fishing gear, so this project aims to test the effectiveness of low frequency whale alarms.”
“In this first instance, we would love to know if the whales divert their migration path or not when they hear a pinger,” said Dr. Slip.
The project involves researchers from Macquarie University tracking the movement of whales from the southern headland of Botany Bay. In the vicinity, a mooring has been dropped offshore with a pinger attached.
“The whale observers aren’t told if the pingers are turned on or off, so the data cannot be biased,” said Dr. Slip.
“We’re hoping at the end of this year’s whale migration period, we’ll have some conclusive evidence to let us know if whale alarms work.” said Dr. Slip.
Project leader, Prof Rob Harcourt from Macquarie University says ‘There has been a huge amount of interest from around the world in the success of this experiment. Entanglement in fishing gear is a major cause of both whale fatalities and horrific injuries and we are hopeful that this research will lead to a solution to this increasing problem.”
The research is a collaborative project between Macquarie University, Department of Primary Industries, The Office of Environment and Heritage and Taronga Zoo.
Humpback Whales migrate from Antarctica to the sub-tropical coastal waters of western and eastern Australia to give birth and mate during winter and spring. Each year at least 1200 humpbacks migrate 5000km to the eastern coast of Australia.