Kina fisherman Peter Herbert, universally known as Herb, slides gracefully off the edge of the tinny in his wetsuit and weight belt. In one hand he has a collecting bag and in the other, a dooka, a two-pronged metal claw with a handle.

“We call it that because when you’re collecting ‘em it goes dook dook dook dook dook,” he explains, demonstrating how he hooks the spiky sea urchins off the seabed and into a bag. It’s a technique he’s been perfecting for 30 years.

Commercial kina fishing is more like old-fashioned pearl diving than industrial trawling. Scuba gear is out. As of this month, dredging is too. Instead, it’s all done by free diving—you harvest as many of the dark, spiky treasures as you can before your breath runs out.

Here, off the northern tip of Hahei Beach on the Coromandel, there are plenty to collect.  On the seabed, glimpsed through the murky water, urchins are everywhere. And there’s not much else—very little kelp or algae, just bare rock.

This is a kina barren: an overpopulation of urchins, signalling an out-of-balance ecosystem. The problem is that the predators are missing. Only the largest snapper and crayfish can crack open a mature kina, and we’ve eaten too many of them. In their absence, the urchins multiply. They mow down the kelp forests that once waved across wide expanses of our coastal waters, and scrape off every fresh frond that unfurls from the rocks.

In the worst barrens, more than 40 kina crowd into a square metre—and they’re both the agent and the victim of their unhealthy proliferation. In this underwater desert, an urchin can persist for decades in a kind of zombie half-life, eating little and producing barely any of the bright, foamy roe—the animals’ eggs or sperm—that (some) humans love to eat.

Many divers, fishers and iwi say barrens are increasing in parts of northern New Zealand—from the Bay of Islands to the Marlborough Sounds.

Not enough science has been funded to say with certainty how far the barrens are spreading or how many kina there are, says University of Auckland marine scientist Kelsey Miller. But the glimpses we have are alarming.

On his dives out of Whitianga, Herb says he’s witnessed an “explosion” of new barrens over the last four or five years. “We are getting a real hiding— everything’s been depleted. The only thing that survives is the kina.”

Exacerbating the problem is the fact that we’re not acting as predators, either. Skinny, wretched barrens kina are considered worthless; customary, recreational and commercial fishers alike leave them in the water.

But what if we could turn this environmental problem into an economic opportunity? Could we harvest these emaciated kina, fatten them up in tanks, and sell them to a vast, roe-loving East Asian market—making money and helping kelp, all at the same time?

A pilot project called Kinanomics aims to test the idea here in New Zealand.

[Chapter Break]

The good news is that barrens are reversible. We’re lucky: in New Zealand the home range of our urchins does not fully overlap with that of our kelp. Some Ecklonia radiata forests still thrive in areas too deep for kina, producing floating spores that can settle and grow into new seaweeds—if they’re not immediately eaten by the spiky horde.

Kelsey’s own studies have shown just how quickly the ecosystem recovers when urchins are removed. During the spring and summer of 2020 and 2021, she and her colleagues spent 450 hours on scuba, armed with hammers and steel pipes. Between them they culled (or occasionally collected) around 90 per cent of the kina from four large barrens in the Hauraki Gulf, leaving the seafloor strewn with spines and shattered shell.

The kelp started growing back almost immediately. Just 18 months later, lush canopies covered a quarter to a half of each of the former barrens. For two years, the kelp forests stayed almost kina-free. The few urchins that remained hid in the cracks and became healthier, Kelsey says. “They have more food, so their roe increases to a better quality within about six months.”

But smashing up kina is not the answer on its own, Kelsey hastens to add. It’s labour-intensive and expensive, for a start. To clear each hectare took a diver 50 hours—significantly longer if they were collecting rather than killing.

The scientists culled around 403,000 kina from the four barrens. But that’s just a drop in the ocean considering the likely extent of barrens around the country. In 2022, University of Auckland masters’ student Lisa Dartnell mapped the shallow rocky reefs around Hauturu-o-Toi/Little Barrier Island and estimated there were about 12 million kina across three square kilometres of barrens.

That’s 3000 tonnes of urchins in total, estimates Kelsey. To cull them would take 15,000 diver hours. Another mind-boggling estimate: the kina population around this one small island weighs in at roughly 10 times the new total allowable commercial catch from the Hauraki Gulf to the Bay of Plenty. Even if we did take them from barrens, fishing for kina will never solve the problem on its own.  We need to change fishing rules to let snapper and crayfish populations recover and do the job for us, or any reprieve will only be temporary. Over time, kina numbers will increase again.

And although this cull was a joint project with Ngāti Manuhiri,  and carried out with the permission of another local iwi Ngāi Tai ki Tāmaki, widespread culling of a taonga kai species sits uneasily with many Māori.

For Ngāti Manuhiri, says a spokesperson Delma O’Kane, the decision to go ahead with the cull was nuanced and careful, and informed by the iwi’s proactive approach to exercising kaitiakitanga.

The cull wasn’t easy for Kelsey, either.

“I’m a vegetarian,” she tells me. “I don’t like killing things. When the kelp grew back, I literally cried because I was like—at least it was worth it. I would personally much prefer to see urchins be harvested rather than culled.”

[Chapter Break]

Johnny Wright surfaces beside me in his camo wetsuit with a loud exhalation from his snorkel. He’s leading the Kinanomics pilot for the consultancy Envirostrat, alongside Ngāti Porou Seafoods and the international startup Urchinomics.

Today, we have a few hours to collect 1000 live urchins from this barren near Hahei before Johnny and his colleague Liam Hansard load them into a truck and drive through the night to Wellington. There, a new home awaits: 36 aquaculture “enhancement tanks” at NIWA’s headquarters in Evans Bay.

This is the third collection trip the team has embarked on at Hahei this year. They’ve done one each season, to assess how the time of harvest and the kina’s reproductive cycle affect growth and flavour. Herb’s given me a collection bag—called a kit—and a dooka so I can try my luck as a kina fisher. Johnny dives again, and this time, I follow him down. With my dooka, I manage to flick four or five prickly urchins into the kit before my lungs start screaming and I kick frantically for the surface.

Johnny has perhaps a dozen in his kit. Herb, on the other hand, can stay down 90 seconds on a good day, and collect 25 urchins at a time—50 on a really crowded barren. He’s been doing this since the early 1990s, when he spotted an opportunity, “took a punt,” and developed a commercial kina industry practically from scratch. He now owns almost 80 per cent of the kina quota in the North Island, and leases most of the rest from iwi quota owners.

Herb wouldn’t usually touch a barren with a barge pole, but he cut a deal with Johnny because he’s worried about the escalating barrens, too. He fears they’ll encroach on the areas he’s been harvesting from for decades, and reduce the availability of kina that are worth fishing.

Around 15 years ago, Herb tried his own kina-enhancement project—fattening up barrens urchins on seaweed. It failed: he managed to boost the roe content significantly, but “we came up against a brick wall of taste”.

This is the main reason why there’s never been a New Zealand kina export industry even though in many parts of the world, sea-urchin roe is a delicacy. In 2016, for example, Japan imported 11,000 metric tons of live sea urchins. High quality roe, eaten fresh or in sushi, can reach more than $300 per kilo there, and the taste for it is growing in other Asian countries such as Korea and Taiwan, too. “The demand is sky-high,” says Johnny.

But people in those countries don’t love the flavour of our kina. They find it bitter, with a metallic aftertaste—perhaps because of the particular kelp our species grazes on. It turns out kina is an acquired taste, like Marmite or feijoas.

But Johnny has a secret weapon. In fact, it’s a secret recipe. He can’t tell me exactly what’s in the feed given to the captive kina—it was developed overseas by Urchinomics, and is trademarked—but he is allowed to say it’s primarily made from offcuts of Japanese kombu kelp which is farmed for human consumption. Urchinomics says the feed does not contain any fish meal or fish oil—in fact it’s fully vegetarian—or deforestation-associated soy or corn, antibiotics, hormones, or preservatives. “It’s been developed to appeal to the preferences of the East Asian market,” Johnny says.

When the malnourished kina we’re collecting arrive in Wellington, they’ll spend three months gorging on this special diet. “Our species responds really well to enhancement,” says Johnny. For a start, kina are robust—after being dooked off the bottom, stacked on a boat in sacks, and enduring 12 hours in the back of a truck bumping along the Coromandel’s busted roads, almost all of the animals survive.

Then, once they’re in the tanks, “they stack on that weight”, says Johnny. The shells themselves don’t grow much, but hidden inside, the roe grows rapidly. It typically makes up less than two per cent of the animal’s weight straight off the barren, but it grows to 10 per cent after six weeks, and reaches 15 per cent—practically overflowing the animal’s shell—after three months.

And what about the all-important taste? The team have assembled an expert panel to judge that.

[Chapter Break]

In Sanford’s Seafood School in downtown Auckland, nine newly minted kina evaluators are tasting roe. The clean, white room is silent and focussed. Four Japanese chefs, a Taiwanese-Kiwi food exporter, a food critic, a Māori kina-lover, and Herb’s son and business partner Todd Herbert sniff samples of kina roe in plastic pottles, and make detailed notes on an eight-page questionnaire.

More pottles cover a nearby table, where Johnny’s tall frame is bent double, categorising the colour of each sample against a sea-urchin colour card. In the Asian market, the roe’s hue matters. “Most consumers go for the yellows, the bright golds—that’s what we expect to be most appealing,” he whispers. But there’s wide variation, from orange to “curry” to dark brown.

There are two roe in each pottle: the gonads of a single kina. Divorced from the prickly animal, they’ve become, simply, food. Up close, they look like a pair of bright nudibranchs, tiny lungs, or tongues complete with fine raised papillae. The tasters don’t know whether the sample they’re given is straight from the ocean—healthy kina I watched Herb collect when we were out four days ago—or from the aquaculture tanks in Wellington.

Todd talks me through the assessment process, which has been devised by sensory scientists who have also guided the development and marketing of such money-makers as kiwifruit, apples, dairy products and wine.

First, Todd analyses the roe’s aroma. Unsurprisingly, there are strong whiffs of brine and seafood—but also of dairy, earth, and sulphur, Todd reckons.

Next, its appearance: Todd scores it for shape, colour and moistness. Is it dry, glossy, glistening, or wet? This one is glossy and sunshine yellow—a perfect colour—but Todd feels it’s let down by an inconsistent shape. Then he slurps. “It’s quite sweet… not very salty. The bitter comes towards the end there. Very tender… definitely a bit creamy. Overall, the entire eating experience of the kina—it was up there.”

On the next table, the exporter Jenny Zo Yang has just finished her last tasting. Jenny—the coolest-looking person in the room in an iridescent navy jacket and stomping Doc Martens—was born in Taiwan and lived in Fiji as a teenager. Since then, she’s loved eating urchins fresh from the sea. “When you have a good kina, the burst of flavour is just so beautiful.”

This is her second tasting trial, and she’s impressed with the team’s progress over the past three months. It seems to her like there’s more consistency compared with wild urchins.

“This trial is actually starting to sway my mind. If I can have a guaranteed good taste in a pottle, then why not?”

Anahera Rawiri (Ngāti Whātua) has been eating kina with her whānau since she was a little girl. Yellow roe might be on trend in Asia, but Anahera prefers the brown. And although it’s a blind tasting, Anahera thinks she can tell which roe came from the tanks. “I do think they taste different. It could be a mental thing that I’m doing, but I prefer the ones out of the sea.”

Japanese chef Makoto Tokuyama, who runs the high-end Japanese restaurant Cocoro in Auckland, tells Johnny he’s hoping for a stronger flavour from the roe, called uni in Japan. “Uni should possess sweetness, creaminess, richness and umami,” he explains to me afterwards. “Kina is a culinary luxury, so it must have impact.” He’d love to serve kina more regularly to his customers, but finds the wild-caught roe too inconsistent in quality and flavour. If Kinanomics can deliver that, he says, “I’m happy to pay the price.”

[Chapter Break]

Kinanomics is still at the slurp-it-and-see stage of industry development. Johnny acknowledges there are a lot of problems to solve before it’s clear whether the idea truly has legs.

Can the team achieve consistently handsome, tasty roe all year round? Will overseas markets pay enough for it to offset the cost of rearing kina in a lab for three months? What’s the best way to get them to Asia—as frozen roe or live animals? Is it economically and practically feasible to harvest enough kina from a barren to allow kelp to return? And how can the team secure a predictable supply of urchins?

For now, Johnny must pay quota-holder Herb by the kilo every time he collects them from a barren. That’s set to become easier. Rachel Brooking, the minister for oceans and fisheries, has just doubled the total allowable commercial catch for kina in two of the main North Island quota areas. (The customary allowance for Māori was also significantly increased.)

Everyone agrees there is no shortage of kina—in the barrens, anyway. Still, Kelsey and some other marine scientists opposed the quota increase because the decision was made without any knowledge of the true kina population. It sets a “dangerous precedent”, they told the minister, to increase the take of any species based solely on fishers’ catch data rather than scientific research.

And increasing the catch on its own, they point out, will do next to nothing to address the problem of kina barrens—since, Kinanomics aside, fishers target everywhere but barrens. Overseas, studies show that commercial urchin fishing can have an impact, but only when it’s strictly regulated to make sure fishers do take from the barrens, and that they remove enough urchins for the kelp forest to grow back. (For kina, you need to get the density down to one urchin per square metre or less.)

Kelsey’s colleague at the University of Auckland, Nick Shears, has related concerns about Kinanomics itself. “It’s business. But it’s being sold to everyone as a solution. It’s not going to address the scale of the problem.” What incentives are there to ensure harvesters properly clear a barren? he wonders. What happens when restoration goals conflict with economic ones? What if clearing enough kina to reverse a barren turns out to be too time-consuming and expensive?

The Kinanomics team admit they haven’t figured out the details yet, though they plan to develop protocols for harvesting and monitoring kina. Ken Houkamau signed Ngāti Porou Seafoods up to the project, and emphasises that for the iwi, rebalancing the ecosystem comes first, “commercial outcomes come second”.

Ken grew up in Gisborne, and his people are from East Cape. He’s watched barrens developing on his home reefs there. He envisions a future where Kinanomics gives employment to whānau in isolated communities: they could tackle their local barrens, enhance the ecosystem, and ensure a supply of wild or enhanced kina for the marae table at the same time.

Still, none of that will be possible if the numbers don’t stack up, Johnny cautions. “If you can’t set up an enhancement operation for a profit, you’re never going to get the secondary benefits of environment restoration or kelp restoration, or the social and community benefits of new jobs. So that’s the first hurdle—can we actually make money from enhancement, can we get the right prices for it? How much does it cost to actually do this? By the end of this calendar year, we’ll have a pretty good understanding of whether or not this is a goer.” After that, they’ll get to work on the restoration part of the plan.

The fisheries rules sitting above all of this are another obstacle, for now. They’re not geared to work with innovation like this. Johnny hopes that instead of relying on quota, Fisheries New Zealand will grant Kinanomics long-term special harvesting permits that would require monitoring and verification of kelp recovery, so that the company can “hand on heart say we have recovered X hectares of kelp”

Similarly, Kelsey suggests a form of “restoration quota” be established to provide incentives for iwi, community groups, or fishers to harvest from barrens—and do the job properly.

New Zealand Geographic tried to sound out Fisheries New Zealand—the fisheries watchdog—on these ideas. We asked for an interview, but received only an unilluminating emailed statement.

[Chapter Break]

Kina are complex—a troubled taonga. Resource, kelp destroyer, identity marker, beloved taste of home and family. Just don’t call them a pest, says Howard Reti, (Ngāti Wai, Ngāpuhi, Te Uri o Hikihiki, Ngāti Tautahi) who loves kina so much he wrote a kids picture book about them, He Pūrākau Kina mō ngā Tamariki, in Māori and English. Kina is his favourite food, and he smiles just talking about it.

“Kina in running fresh water, kina in cream, kina on toast, you name it. The taste is unmatched—it’s rich, and connecting. You connect it to the sea. And you connect it to all the other people who have eaten kina before you. When you brought kina onto the table, you held mana.”

His sisters always craved kina when they were pregnant, he says— “and you’d better go get it for them or you’d be hung out to dry!”

Howard is a member of the Mid-North Iwi Fisheries Forum, which opposed increasing the kina quota for similar reasons to marine scientists Kelsey and Nick: because the group advocates for a cautious approach to fisheries, and kina populations haven’t been properly quantified.

Fifty years ago, Howard’s aunties taught him that after he’d filled his kete he should spend 10 minutes breaking open a few kina he’d left behind, effectively serving up a feast for predators. “They knew that we need to help the big snapper and the big crayfish to keep the kina in moderation. Culling is [part of] what we’re taught to help keep the balance, as part of our role as kaitiaki.” Here is mātauranga at work, providing a precedent for Kelsey’s work with the hammer.

To fix kina barrens, we need all the tools we can muster, and we need them all at once. Markets are fickle, and pinning restoration entirely on the whims of East Asian consumers or the goodwill of fishers seems unwise. In some places, Kinanomics may help communities to deal to their local barrens while making a profit. In others, culling might be the best short-term solution—though people shouldn’t rush out with a hammer, Kelsey cautions. Without a permit, “it’s illegal, unethical, and potentially culturally inappropriate—and unless it’s done systematically and on large scales, kina will move back in.” Restoring large-predator numbers through catch limits, size limits, or marine protection has to happen as well, she emphasises, though this will take decades.

For many Māori, kina have long been a seasonal tohu, a sign—when the pōhutukawa flower, the kina are fat. Now, they’re becoming a tohu of another kind: a barometer of the state of our troubled oceans, a prick to our collective conscience. Each of the spines represents one of our misdeeds when it comes to the moana, Howard suggests.

“I could come up with a thousand points of what was done to the ocean to make the kina a pest. It’s a gauge that tells you what’s there—and if you don’t get it right, it’ll poke you in your feet or your fingers.”