A new study exploring the health of dolphin airways has revealed findings that could help save endangered whale species.
During an eight-month study at Seaworld on the Gold Coast, Dr Catharina Vendl from the University of NSW analysed samples from the airways of both sick and healthy dolphins.
Dr Vendl found the first long-term evidence that dolphins have their own individual ‘signature’ bacteria in their airways.
‘This discovery means that there is a good chance that these bacteria are indicative of the dolphins’ health, as the bacteria interact with the host’s immune system, like bacteria do in the gut,’ Dr Vendl said.
‘Dolphins and whales are closely related. Whales harbour bacteria in their airways in a similar way to dolphins. Therefore, I suggest that the health of whales can be assessed by testing the whales’ airway bacteria.’
Dr Vendl said the aim behind her research was to find out if the airway bacteria can be used as biomarkers for the health of dolphins and whales.
‘This area of research is still relatively new and essential knowledge about the airway bacteria of cetaceans is lacking,’ she said.
‘This is because it is virtually impossible to take a blood sample from a whale in the wild to assess its health status.
‘Sure, we know that every mammal has gut bacteria that interact with its host, such as in its immune function and digestion.
‘Those bacteria are specific to the individual, but also specific to the species.
‘However, for the bacteria in the ceteceans’ airways, we still know very little about how host and species-specific they are.’
Until now, researchers have also lacked crucial knowledge on the long-term stability of the airway microbiota and its potential changes when the whales and dolphins are sick.
‘We would have liked to take blow samples of the same whales over several months, but this is not possible, because the whales migrate and we can’t follow them all the way up and down the coast to continuously take samples from them,’ Dr Vendl said.
She said the Sea World dolphins’ controlled living conditions provided a lot of extra information that they couldn’t get from wild dolphins or whales.
‘For instance, we knew their age, their sex and the dolphin trainers also reported if they were sick or healthy,’ she said.
‘So it was much easier to correlate the data of the airway microbiota with other parameters of the dolphins. We found for example that there was a difference between the bacteria of the females and the males. We would not have been able to see such things in whales we have studied, as we were not able to determine their sex.’
Potential conservation measure
She said this latest discovery could help protect endangered cetaceans such as the northern right and blue whales.
‘In order to put efficient conservation management strategies in place, it is crucial to know what the underlying issues of a whale population is,’ Dr Vendl said.
‘For instance, a whale population could be doing poorly because it has trouble reproducing so that the population can’t recover.
‘Or the remaining whales in a population might suffer from poor health due to human stressors or pollution in the oceans.
‘We can only address these issues properly, if we have an idea about the health status of the whale population.’