New Zealand's Iconic Yellow-Eyed Penguins Could Be Extinct Locally In 40 Years

Climate change and other effects of human activity are driving the endangered penguin to the brink.

The rare yellow-eyed penguin, or hoiho, is one of New Zealand’s most iconic and beloved animals.

Every year, hundreds of thousands of tourists and visitors flock to the Otago Peninsula in Dunedin, New Zealand, to get a peek at the famed penguin, named for the band of bright yellow that runs from its eyes to the back of its head.

“It’s a high-profile species here,” ecologist Thomas Mattern told HuffPost from Dunedin on Thursday. “We even have it on our $5 bill.” 

The penguins are estimated to contribute about $70 million (or 100 million New Zealand dollars) to the local economy every year through tourism. “At every airport in the country, you’ll find the yellow-eyed penguin on huge billboards,” said Mattern, a researcher at the University of Otago. “It’s a huge draw.”

But according to research recently published by Mattern and his colleagues, penguin enthusiasts may soon be disappointed when they visit the Otago Peninsula, located on the east coast of New Zealand’s South Island. The yellow-eyed penguin is in great peril on the peninsula ― and on the New Zealand mainland as a whole, researchers found. Climate change and other effects of human activity could drive the species extinct locally in just 40 years.

The population of yellow-eyed penguins on the Otago Peninsula has been falling precipitously over the past two decades. “We used to have about 600 to 800 breeding pairs in the mid-1990s, but we’re now down to 200 to 250 breeding pairs,” Mattern said. “That’s a loss of 75 percent.”

Rising ocean temperatures have been a major cause of this decline, according to the new paper, published in the journal Peer J earlier this month. Warming has reduced the amount of food available to the penguins, which feed off the ocean floor.

But climate change hasn’t been the only culprit. By studying penguin population records dating back several decades, and using prediction models developed to estimate the effects of global warming and other threats to the species, Mattern and his colleagues found that while one-third of the population change was due to rising temperatures, the remaining two-thirds was linked to other human activities.

Data on these other threats is currently limited, but researchers believe the fishing industry may play a significant role. Gill nets used by fishermen are known to ensnare yellow-eyed penguins, which get entangled in the near-invisible nets and drown. A 2000 study that looked at autopsy data of 185 yellow-eyed penguins that died around South Island found that more than 70 deaths were linked to gill net entanglement.

The pollution of waterways from urban centers and also from farms in the area may also be a significant driver of penguin deaths. “There’s some really bad stuff being flushed out of the sewer system into our rivers and seas,” Mattern said.

The yellow-eyed penguin is named for the band of yellow that runs from its eyes to the back of its head. 
The yellow-eyed penguin is named for the band of yellow that runs from its eyes to the back of its head. 

Considered an endangered species by the International Union for Conservation of Nature, the yellow-eyed penguin is one of the rarest penguins on the planet. Endemic to New Zealand, the bird is found in three distinct clusters. About 40 percent live on the New Zealand mainland ― mostly on the Otago Peninsula and also further south on Stewart Island and Codfish Island. (New Zealand is a country made up of about 600 islands. The “mainland” is usually defined as the archipelago made up of the North Island and South Island, and the smaller islands located nearby). 

The rest of the yellow-penguin population lives on the remote subantarctic Campbell Island Group and Auckland Islands, which have no permanent human inhabitants. 

Of the three clusters, the yellow-eyed penguins on the mainland are under the greatest threat of extinction, Mattern said. “If you look at the penguin species around the world, the ones really under threat are the ones that live and breed close to human settlements. The closer they are to humans, the greater they are in peril.”

The new study focuses specifically on the penguins on the Otago Peninsula, but Mattern said the populations on Stewart Island and Codfish Island are in as much or more danger

“They’re probably even worse off,” he said. The risk of climate change is the same and by-catch is as much of a problem, but the area is also home to a multimillion-dollar oyster fishery, which Mattern said has destroyed most of the penguins’ habitat.

“Penguin numbers on Stewart Island have declined since the mid-1990s. On nearby Codfish Island, penguin numbers have been in freefall for a few years now,” he said. “We are looking at a likely extinction of the [entire] mainland cluster by 2060.”

Mattern said people may point to the two subantarctic clusters as a reason to not worry about the yellow-eyed penguin on the mainland. “If the penguins disappear here, they can just say, well, we still have them on the subantarctic islands.” 

But Mattern stressed that the loss would still be deeply felt. The three clusters are entirely distinct from each other, he said, and “if we give them long enough, they would evolve into three different species.”

If one of the clusters is lost, it will be “gone for good,” Mattern said. “There can’t be any hope that it will be recolonized.”

A yellow-eyed penguin on the Otago Peninsula stares out at the ocean. 
A yellow-eyed penguin on the Otago Peninsula stares out at the ocean. 

The disappearance of yellow-eyed penguins from the mainland could be a significant blow to the New Zealand economy. “I hate to talk of wild animals in terms of monetary value,” said Mattern, but losses could rack up to hundreds of millions of dollars.

More critically though, the vanishing penguins would be a harbinger of deeply troubling ecological changes. 

“Penguins are canaries in the coal mine when it comes to ocean health,” Mattern said. “They are at the top of the food chain so they are usually the last one to leave the room and switch off the light. If they’re gone, then we know that the entire marine ecosystem is off-kilter. We should see them as a warning sign of a dying ocean.”

Fortunately, Mattern said, there is still hope for the yellow-eyed penguin and the habitat to which it belongs. “All is not yet lost,” he said. “We haven’t reached the critical threshold.”

He said he hopes the new research will spur prompt action to save the species on the mainland. The penguin populations can still recover if swift and effective conservation measures are implemented. Gill net bans or other methods to mitigate by-catch could be introduced. Marine reserves could be established to protect seafloor habitat, and actions could be taken to reduce pollution from agricultural practices and runoff from urban areas. 

“We need to get organized,” Mattern said. The yellow-eyed penguins are depending on it.