Whales unfazed by Macquarie scientists’ mix tape alarm tunes
An international team lead by Macquarie University researchers has found that humpback whales are not only unfazed by complex alarm sounds designed to alert them to hazards like fishing gear, they have no response to these warning sounds at all.
The research team tested whether ‘complex’ whale alarm sounds, instead of previously tested simpler ones, could influence the whales to avoid potential hazards.
“We used louder sounds combined with complex tones to see if this would work to deter the whales,” explained lead author and Macquarie Department of Biological Sciences PhD student, Vanessa Pirotta.
To test their new sounds, the researchers moored a whale alarm to single unit fishing gear, such as a lobster pot, in the middle of the so-called ‘humpback highway’ off the Sydney coast during their 2013 northern migration, and used a theodolite—a surveyor’s tool—to track the animals’ movements in response to the new alert signals. However, the whales appeared not to respond, continuing to surface and travel in the same direction as normal.
“The lack of measurable response suggests that these new types of tones are not likely to be effective in alarms intended to reduce entanglements for the northward migrating humpback whales,” Ms Pirotta said.
“While we haven’t yet cracked the whale code in terms of warning sounds, we are still learning a lot about the types of alerts that these animals will and won’t react to,” she added.
The study builds on previous work by the same research group, which tested whether a simple and commercially available whale alarm designed to warn whales about the presence of dangerous fishing equipment elicited a response in whale behaviour.
“In the previous study we wanted to see if whales would avoid fishing gear when a simple alarm was turned on versus when the alarm was off. Much like your mobile phone or GPS, the idea of a whale alarm is to alert whales of something, in this case the presence of fishing gear, so that they move away from danger,” explained Ms Pirotta.
“Unfortunately, the research suggested that simple alarm sounds were also not effective in preventing whale entanglement at least for single unit fishing gear such as lobster or crab pots as we tested,” explained Ms Pirotta.
While “Dory” made it look very easy to speak whale in Finding Nemo, it appears that scientists still have their work cut out for them when it comes to producing warning alerts in humpback lingo. However, the cause is an important one, with humpback whales frequently getting entangled during their northern migration in barriers such as shark nets, with the most recent case involving a humpback calf only months ago.
Macquarie Department of Biological Sciences
The Macquarie Department of Biological Sciences is a vibrant community of teachers, researchers and students working across a wide range of disciplines including animal behaviour, climate change, conservation, ecology, evolution, genetics and genomics, paleobiology and physiology.
Teaching and research assets include world-class modern digital labs for teaching, outstanding newly updated labs and glasshouses for plant growth experimentation, a new sea water facility for conducting experiments in marine systems, a large fauna park allowing observational studies of animals in natural environments, and a range of cutting-edge molecular biology research laboratories. The department also houses a large collection of biological specimens in its arboretum, herbarium and museum that are used for teaching and community engagement.
Macquarie University’s close proximity to Lane Cove National Park and the Macquarie Ecology Reserve also means that students can undertake practical work in the field, ensuring they develop valuable skills and problem-solving abilities, just a short walk from campus.