Battle of the barrens

In the battle with kina barrens, underwater deserts where the sea urchins have taken over, Dr Kelsey Miller has more hands-on experience than just about anyone.

Donning her scuba gear, the marine scientist led colleagues and supporters in hundreds of dives to remove kina from the barrens on shallow rocky reefs in the Hauraki Gulf during the spring and summer of 2020 and 2021.

When Oceans and Fisheries Minister Shane Jones cites the presence of 400,000 kina on just 7.1 hectares (0.07 square kilometres) of reef as an illustration of an “industrial-sized, industrial-grade” problem, he’s talking about Kelsey’s PhD project, which involved laboriously removing those urchins one by one.

Happily, her work showed that removing kina was extremely effective in rapidly restoring lush forests of the brownish kelp Ecklonia radiata.

“That just wasn’t expected,” says Kelsey. “The seaweed grew back naturally without anyone’s help; there was no need to ‘seed’ it. Simply removing the kina achieved so much.”

Now, Kelsey, a research fellow based at Leigh Marine Laboratory, and Dr Nick Shears, who supervised her PhD, are advising policy makers, iwi, fishers and local communities on how best to tackle barrens. The pair were among the scores of people at a hui hosted by Jones at the historic Awanui Hotel in the Far North on 10 May.

Kelsey and Nick say increases in recreational catch limits for kina alone would achieve little; instead, special ‘restoration’ permits are better for large-scale, systematic, effective removal. However, overfishing of kina predators like tāmure (snapper) and kōura (spiny lobster), is the underlying problem, and addressing this is the long-term solution.

For Kelsey, the kina work is the latest phase in a life devoted to the natural world, particularly the ocean.

Living at Ōmaha, within earshot of the waves, she spends as much time as possible in the water, including as a free diver, ocean swimmer, surfer and an underwater hockey player.

Growing up, her family spent half of each year on the remote and sparsely populated Quadra Island in British Columbia, home to wolves, otters, deer and cougars, and visited occasionally by black bears, which would swim from a neighouring island to steal apples.

Nature minded and mobile, the family also lived in the US, Central and South America and Southeast Asia.

As a young woman, Kelsey operated a US based family wholesale crabmeat business, dealing with crab boats in Thailand. She went on to become a fisheries observer on fishing boats in the Pacific Ocean, along the coast from California to Washington, and in the Maldives, recording information on bycatch, fuel use and species interactions.

After becoming a marine scientist, Kelsey was drawn to New Zealand by our high-quality research into the kelp problem, which she knew from North America, where urchins have destroyed almost all of California’s coastal kelp.

Around the world, kelp forests provide homes for marine life, limit the erosion of coastal land, produce oxygen and food, and sequester carbon. They’re like an underwater Amazon forest. But they are disappearing at an estimated rate of 1.8 percent per year – twice as fast as coral reefs and four times quicker than tropical forests, Kelsey points out.

Laborious kina removal work for Kelsey’s PhD project involved cracking and crushing kina with metal pipes or hammers, leaving their roe to be eaten by other sea creatures. A small portion were able to be harvested for iwi.

“It’s not easy diving,” Kelsey says. “You’re huffing and puffing, it’s really hard work.”

A repetitive strain injury requiring a wrist brace resulted from her biggest single daily removal of 10,000 kina. All up, the project took 900 hours of diving by Kelsey and her colleagues and supporters: 450 hours for removal work and 450 hours of monitoring.

“I don’t like killing kina; I don’t like killing anything. It was very unpleasant,” she says. “But seeing the recovery from a barren to a huge kelp forest made it seem worthwhile. It just blew me away.”

Iwi have mixed views on culling a taonga species, but in this case Ngāti Manuhiri and Ngāi Tai ki Tāmaki supported the research, which was carried out under a government scientific permit, to understand how the mauri of the rocky reefs might be restored.

In Aotearoa, declines in large snapper and spiny lobster, capable of cracking open a mature kina for a meal, have seen kina take over an estimated 14 percent, or 30 square kilometres, of the coastal rocky reef in the north-eastern upper North Island, from Tāwharanui in the south to Maitai Bay in the north.

This seems to be the worst-affected area, but barrens are dotted around the country.

With everyone keen to help, Kelsey is flagging that the solution isn’t as simple as rushing to the sea to grab a feed of kina.

For one thing, kina from barrens are often not good eating; smaller and somewhat starved, living on in a kind of hibernation once the kelp is gone, their roe doesn’t taste as good.

This limits the potential to harvest them for kai. (There are ambitious plans to harvest malnourished kina then feed and fatten them in land-based facilities.)

Haphazard removals of kina won’t achieve much without long-term and systematic planning, since, until lobsters and large snappers stage a revival, continued removals by culling or harvesting will be needed – a one-off burst won’t do it.

And dropping ‘green gravel’, small rocks seeded with kelp, into barrens will feed kina rather than rebuild kelp forests unless kina are cleared first.

“The long-term solution is for the big predators, the snapper and the spiny lobsters, to return, which would require more restrictions on fishing,” says Kelsey.
“For the short-term, however, we now know we have an extremely effective method for restoring these beautiful forests.”

Next, she plans to create a guide book for community groups, hapū and iwi on kina removal, and to research the detail of why kelp recovers better in some places than others.

One thing she knows: kina are not the enemy.

They’re remarkable creatures, responsible for underwater coastal choruses at dusk and dawn like those of birds in a forest.

The noises are the sound of the urchins eating by scraping algae off rocks with their protruding teeth. The noises are amplified by the creatures’ hard, dome-shaped bodies.

In the right numbers, they are not a problem and are an important part of the ecosystem.

“We’ve demonised them,” says Kelsey, “but it’s not their fault – they’re just out there trying to live their best lives, eating when they are hungry.”

Paul Panckhurst