Hector’s dolphin has a problem – at least, one of them does. Cephalorhynchus hectori, as these aquatic explorers are technically called, are the only endemic cetaceans to New Zealand, and it appears one of them has a bit of a broken blowhole.
Discovered in the waters off Christchurch in 2014, researchers found that it was unable to use what is essentially its head nostril to breathe. Unsurprisingly, most dolphins would die without the ability to take in air, but this particular adult C. hectori can stick its head out of the water at a steep angle and breathe through its mouth.
This is the first recorded incidence of a dolphin being able to breathe in this way. Dolphins in general have long been acknowledged as incredibly intelligent creatures with social hierarchies and complex vocalizations, and this clever little survival characteristic is another piece of evidence beautifully showcasing this.
The team – led by Professor Stephen Dawson, a marine conservation biologist and expert on Hector’s dolphin at the University of Otago – points out that “in all other respects the ‘mouth-breathing’ dolphin seemed normal, and appeared to be in good physical condition,” so it’s not clear what’s wrong with its blowhole. Perhaps it suffered an internal injury, or a foreign object got sucked in and remains lodged there.
The novel dolphin in action. New Scientist via YouTube
As noted in the journal Marine Mammal Science, captive dolphins have previously been seen to blow bubbles from their mouth as a recreational activity within their squad. However, these bubbles weren’t created by inhaling and exhaling through the mouth. Instead, these were bubbles captured within water vortexes around them.
Either way, this sign of higher cognitive reasoning is good news for conservationists – as of 2011, Hector’s dolphin, the smallest marine dolphin in the world, had seen its population reduced to around 7,000 from far higher figures a few decades ago. As is almost always the case, human activity is to blame, with overzealous fishing practices causing many of these dolphins to become entangled in near-shore nets.
There are two subspecies of C. hectori. The first, C. h. hectori, is found around the South Island, as is relatively numerous compared to C. h. maui, or Maui’s dolphin. This unfortunate group is considered to be critically endangered, and as of the last few years, there are only 55 left.
Times are tough for this particular cetacean, and it’s not clear whether the Maui subspecies will ever recover. The other subspecies, however, is bouncing back – it now numbers between 12,000 and 18,500 in the wild, meaning its population has doubled in size in just five years.
Aerial surveys had found previously unseen populations in waters several miles away from the coast, far away from coastal fishing trawlers. This means that they had either begun to breed there when threatened near land, or, more likely, previous dolphin surveys had severely underestimated their numbers, as researchers had assumed they only inhabited coastal waters.
“We have made some evolutionary steps forward, so it is kind of nice, little New Zealand working on their little dolphin,” Deanna Clement, a marine mammal ecologist at the Cawthron Institute who led this year’s extensive aerial survey, told Stuff. “Now these can go out and be applied to a lot of other countries and a lot of other species.”
Either way, it was good news for all concerned, but as Clement pointed out, it doesn’t mean that this subspecies is no longer under threat.
The decline of the Maui subspecies. AFP News Agency via YouTube
[H/T: New Scientist]