Dolphin ‘signatures’ used by scientists to track pods more easily
SCIENTISTS will be able to use dolphins’ “names” to track them after British researchers identified the signature whistles of a whole pod for the first time.
Dolphins make a wide variety of noises, but the most useful one for scientists is their “signature whistle”, which they use like a name to identify one another. Recording and identifying the whistles mean the pod can be tracked wherever it is heard.
Researchers from the University of Plymouth put underwater microphones off the coast of Namibia, and went through thousands of hours of recordings to capture the individual noises. Emma Longden, who led the study published in the Journal of Mammalogy told BBC Radio 4’s Today programme that she hoped this method would be used off the coast of the UK, so dolphins could be easily and cheaply monitored year-round.
She said: “There are many cetacean species around the UK and this method will hopefully also be used to monitor them. It’s also much cheaper than getting humans out there.” It means scientists can study the creatures, which are under threat from fishing and climate change, and monitor their numbers without having to send humans to remote spots.
Researchers hope the method can also be used to track other species, with a focus on endangered species such as humpback dolphins. It will mean that more of the ocean can be mapped, and individual dolphins will not be counted or tracked more than once if they pop up in different, farflung places.
Ms Longden explained: “Bottlenose dolphins produce quite a wide variety of sounds, and their signature whistle is used almost like a name.
“It is individual in the respect that it just belongs to one animal. How we estimate the population is using a method called mark recapture; we capture it on hydrophones. By capturing it at different places we can count the number of animals and estimate their range.”
She analysed more than 4,000 hours of acoustic data from four hydrophones positioned along the Namibia coast.