Kate Evans visits a passionate team as they carpet a remote volcanic island in Tonga with poisoned bait, hoping to eradicate rats. What does it take to complete this kind of project, what are the chances of success, and what will it mean for the island's ecosystems if they manage to remove the rats once and for all?

Rat eradication from islands is a team sport. It's not a competition - but if it were, New Zealand would surely be up there. That's why on most pest removal teams around the world you can probably find one or two Kiwis right in the thick of things.

It takes a village

A team lined up to complete the rat eradication project for the island of Late in the kingdom of Tonga is no different. The New Zealand Department of Conservation is supporting the operation and have provided some skilled staff. The helicopter team (pilot, engineer, ground crew) are all Kiwi too.

They're joined by a project manager from the NGO Island Conservation, and Tongan conservationists from the national environment department.

Years of feasibility studies, finding funding, planning and logistics have come down to this - a second, and final, aerial application of poisoned bait across the island.

Island paradise

It may not be what you picture when you think of a tropical island, but its jagged basalt cliffs and remoteness has made volcanic Late a potential wildlife haven.

Here you can find the Tongan whistler and ground dove, two rare birds on the IUCN red list of threatened species. And it has the habitat needed for the malau - the Tongan megapode - to breed. Malau don't incubate eggs by sitting on them, instead they bury them in warm volcanic soils and sands, and Late's smoking surface is perfect.

Rat eradications elsewhere have allowed forests to rejuvenate, land birds to rebound and seabirds to return. The bird guano ripples the effect out further - feeding the coral reefs and allowing nearby ocean ecosystems to flourish.

Science journalist Kate Evans joins the team on the last day of bait spreading, in what they hope will be the first day of a bright future for the island and its inhabitants. …

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Journalist Rebekah White meets two people who have been counting albatrosses on remote islands in the subantarctic for more than three decades. Their research shows that at least one species is en route to extinction. A few changes to the way we fish could save it.

Gibson's and Antipodean albatrosses are citizens of no one nation. They are ocean birds, living on the wind and waves, travelling massive distances, passing back and forth over the high seas and the imaginary boundary lines we draw on maps.

But when they land to chat, to flirt, to lay an egg and raise a chick, they come to two of New Zealand's subantarctic islands.

Three decades of albatross study

And when they return, some of them meet with two familiar human faces.

Across the last 34 years, Department of Conservation researchers Kath Walker and Graeme Elliott have been visiting these islands to count the birds, and to study them.

At first everything seemed fine. In the early 1990s numbers were low but increasing. Things were positive. Then came the summer of 2006/2007. There was a population crash, reason still unknown, and on both islands, albatross numbers plummeted.

These albatrosses don't breed until they at least eight-years-old, only breed every two years, and tend to mate for life. Since the crash, Gibson's albatross numbers have come back slightly, but Antipodean albatross numbers continue to decline.

And adult birds, especially females, are still going missing.

Hooks don't discriminate

Tuna fishing boats use a method called surface longlining to catch their prey. The lines can be up to 100 kilometres long, with thousands of hooks.

Squid is used as bait, a tasty morsel for tuna. Unfortunately, albatrosses agree.

Using satellite tags Graeme and Kath have watched missing albatrosses' paths overlap with those of boats, and in one case, in which leg bands and the satellite tag were returned to them, follow the path of the boat.

Listen as science journalist Rebekah White explores the albatross bycatch problem, and what we could do about it. …

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New Zealand once led the world in marine protection. Now it looks like we will fail to meet our international promise to protect 30 percent of our ocean estate by 2030. Why is stopping fishing so politically fraught? How might our ideas about marine protection need to change? And why, when our seas are in need, is it taking us so long to learn to talk to each other?

This is an updated excerpt from the July - August 2023 New Zealand Geographic feature article 'Taking on water'.

In 1975 five square kilometres from Cape Rodney to Okakari Point was made a marine reserve, the first in New Zealand, and possibly, the world.

"Nothing to do at Goat Island anymore," declared the local newspaper.

Three hundred thousand people now visit every year. And research indicates that this small, protected patch is helping to contribute fish to surrounding areas.

Lunching on experiments

The Marine Reserves Act was created in 1971 in response to campaigning by the late Bill Ballantine, among others. He was director of the University of Auckland's Leigh Marine Laboratory which was established in 1964. But staff and students soon discovered people were eating their experiments.

So that's what the Act was created for: 'the purpose of preserving, as marine reserves for the scientific study of marine life, areas of New Zealand that contain underwater scenery, natural features, or marine life, of such distinctive quality, or so typical, or beautiful, or unique, that their continued preservation is in the national interest.'

Today, with our ocean ecosystems under increasing pressure from commercial and recreational fishing, sedimentation, pollution, and warming, we need our marine protection to do more than preserve small areas for scientific study.

But it's not an easy task. Most marine protection proposals face extensive push back that delays the process for years, sometimes decades.

"It's really, really hard to manage it appropriately," says Professor Chris Hepburn, marine scientist at the University of Otago. "It's land, sea. It's different user groups, it's rights, it's things like the settlement, it's people not understanding each other's points of view."

The act that ignored the Treaty

'The settlement' is the Treaty of Waitangi (Fisheries Claims) Settlement Act 1992, an attempt to restore some of the rights taken from Māori when it comes to fisheries…

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The Bounty Islands are tiny in terms of area - just some bits of granite jutting out of the ocean. But they are huge in terms of seabirds. James Frankham joins a team researching the erect-crested penguins who breed in this remote archipelago. Recent counts suggest the penguins of the Bounties are doing fine. But this is not the case on the Antipodes Islands, and the researchers desperately want to know why.

The Bounty Islands jut out of the water like giant granite fins. Steep and sheer, with no greenery in sight. They are covered instead by a mottled white - guano or bird poo from the tens of thousands of penguins and albatrosses that come here to breed.

The least studied penguin

The Bounty Islands is one of two remote, subantarctic island groups home to the erect-crested penguin. Stout and handsome, with bright yellow crests that look like elaborate punk rock hairdos, their remote breeding sites means they've not been studied in depth.

But Dr Thomas Mattern of the Tawaki Project plans to change that.

Good news and bad

Using drones to make photo mosaics of all the Bounty islands, Thomas has counted each penguin breeding pair and arrived at a number that suggests the Bounty Island population of penguins has remained relatively stable since the mid-1990s. Good news.

Not the case for their other breeding sites at the Antipodes Islands, where early evidence suggests a significant decline.

But these island groups are a mere 200 kilometres apart - a hop, skip and a jump in penguin swimming distance. How is one group seemingly doing fine while the other is in trouble?

New Zealand Geographic's James Frankham joins an expedition to these remote and wild islands as the scientists begin to unravel this mystery.

Learn more:

• Read the accompanying New Zealand Geographic article by James Frankham, with photography by Richard Robinson.
• As part of this expedition Claire Concannon also visited the Antipodes Islands to learn how they have fared since mice were eradicated.

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What roles do our ocean ecosystems play in capturing carbon? Kate Evans speaks to iwi Māori working to improve the health of an estuary in the Bay of Plenty, and to scientists studying the fiords of New Zealand's southwest coast. There's potential for huge amounts of carbon to be locked away, if we don't mess it up. 

To avert the worst of the climate crisis we need to reduce our emissions. One way is to phase out fossil fuels, to leave forms of carbon like oil and gas locked up in the ground. But we can also look at ways to lock up more carbon, long term. And some options for this are in our oceans.

The champ of champs

Between 6-10 metres of rain falls in Fiordland each year. An incredible amount. It's part of what powers the forest-to-fiord carbon storage pump that makes Fiordland exceptionally good at locking away large amounts of carbon long-term. Something scientists are only beginning to understand.

Return of the wetland

Luckily, National Park status on land and marine protection in part of the sea have meant that Fiordland has remained relatively untouched.

Not so for some of our other carbon-burying ocean ecosystems. Salt marshes and seagrass meadows in estuaries have taken big hits. But Te Whakapū o Waihī, a collective of local iwi and the Bay of Plenty Regional Council, are fighting back.

Listen as Kate Evans learns about Fiordland's secrets, the plans to restore Waihī wetlands and estuary, and what this all means for our blue carbon potential.

Learn more:

• Read the accompanying New Zealand Geographic article by Kate Evans, with photography by Richard Robinson.
• Alison Ballance previously reported on the work of the Cawthron Institute to collect and grow seagrass seeds.
• Justine Murray joined Professor Kura Paul-Burke out on the Waihī estuary mud flats last year to learn about tohu (signs), nana (seagrass) and tuangi (cockles).
• Parts of the Southern Ocean also acts as a carbon sink, but there are concerns this might change.

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People and livestock gobble so much fish that the seas soon won't keep up. Is the answer to grow fish on land? Kate Evans meets scientists figuring out the puzzles of how to farm some of New Zealand's iconic ocean creatures.

Many of our fisheries are under pressure. At the same time people are eating more fish. Could farming iconic New Zealand species be the future? And what are the advantages of growing fish on land?

A new lease of life

Ocean Beach used to process lambs, a record of 20 000 in one day, but now it's gullies and troughs run with seawater, not blood. Home to the New Zealand Abalone company and Manaaki Whitebait it's become one the frontiers of New Zealand aquaculture - growing fish indoors.

Pāua puzzles and whitebait mysteries

It's not an easy task. Growing fish on land means taking responsibility for their needs throughout their life cycle. First you must identify those needs, account for them in an indoor setting, and make the whole process as efficient as possible so you can still turn a profit. It takes trial and error, and patience.

Learn more:

• Read the accompanying New Zealand Geographic article by Kate Evans, with photography by Richard Robinson.
• Seaweed is also being farmed in a specialised warehouse space in Tauranga.
• Recently the green light has been given for an open ocean salmon farm in the Cook Strait

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Kina numbers are exploding on some of our reefs, decimating seaweed habitats. Could this problem be solved by eating them? Kate Evans investigates the potential of kina-nomics.

The kina are out of control. As many as 40 urchins crowd into a single square metre of rock, devoid of other life.

A kina barren is a symptom of an ecosystem out of balance. Could we eat our way to a solution?

Kina zombies

Kina numbers have exploded as we've eaten too many of their predators - like big snapper and crayfish - that usually keep them in check.

The urchins munch through kelp and seaweed, leaving bare rock and little else. The kina themselves end up suffering too - they persist in these zones as zombies, eating little and barely producing any roe.

Luckily, these barrens can be reversed and kelp forests restored when the kina are removed.

Putting kina on the table

Kina-nomics involves taking starving kina off reefs, fattening them up and selling them to an East Asian market.

But how can the kina be made more consistently tasty? And can economic and conservation goals really align?

Listen to the episode to dive under the water with a kina harvester, taste some kina, and untangle whether a commercial harvest of these spiky taonga can really fix kina barrens.

Learn more:

• Read the accompanying New Zealand Geographic article by Kate Evans, with photography by Richard Robinson.
• Check out another effort to restore kelp forests with the Love Rimurimu project in Wellington, profiled in a recent Our Changing World episode.
• Jesse Mulligan spoke to another researcher studying kina removal in the Marlborough Sounds.

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Crackle, pop, woof, crunch, click. In the ocean, an undersea orchestra is in full swing. Journalist Kate Evans discovers who's playing in it and why, and what happens when human noise drowns out this symphony in the sea.

Symphony in the sea

Journalist Kate Evans and presenter Claire Concannon discover a world of snapping shrimp, singing whales and barking John Dory.

Researchers Professor Craig Radford and Dr Jenni Stanley are uncovering more about the orchestra harmonising under the waves - who's playing in it, and why they are making these sounds.

Plus, what impact is our human noise - like boats - having on ocean creatures?

Learn more:

• Read the accompanying New Zealand Geographic article by Kate Evans, with photography by Richard Robinson.

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A collaboration between Our Changing World and New Zealand Geographic, the Voice of Tangaroa series explores the state of our oceans, and the extraordinary variety of life that calls it home. 

93% of New Zealand is covered in salt water. 80% of our biodiversity is in our seas. And yet this is the part of our realm we understand the least and treat the worst.

A collaboration between Our Changing World and New Zealand Geographic, the Voice of Tangaroa series explores the state of our oceans, and the extraordinary variety of life that calls it home. 

From kina-nomics, to the undersea sound, from growing fish on land, to the debates around our marine reserves - science journalist Kate Evans has been diving into the complexities of how we think about, enjoy, manage and use our oceans, and what this means for the creatures that live in it.

Now, with production help from RNZ's Our Changing World team, and original music composed by Wellington band Grains, you will be able to hear the voices of the characters involved and experience the sounds of our underwater realm.

Voice of Tangaroa is a joint production between RNZ's Our Changing World and New Zealand Geographic.

Reporting for this series is Public Interest Journalism funded through NZ On Air. You can learn more and read the articles for free at www.nzgeo.com/seas

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