When kelp disappears, the people who rely on it suffer. Around the world, coastal communities are being mustered into action. Is it enough?
John Minehan is an environmentalist, he says, but only out of necessity.
He makes a living diving for abalone off the coast of Mallacoota in Eastern Victoria, a dangerous and highly skilled job he’s been doing for decades now. A job he loves.
“Sometimes I close my eyes on the way down and I wait till I hit the bottom and I bury myself in amongst the kelp forest and I feel safe,” he says.
Abalone used to thrive in the cold grey waters of the Bass Strait, fused to the reefs and hidden among the kelp.
But something changed a few decades ago and divers started noticing increasing numbers of Centrostephanus rodgersii, a sea-urchin that will eat a kelp forest down to bald rock if you let it.
Many of the underwater forests John had visited for years disappeared, replaced by thousands upon thousands of sea-urchins.
“It was quite daunting to lift your head and see these urchin barrens seeming to extend forever,” he says.
“You’d think ‘oh my god, how are we ever going to get on top of this?'”
Then the abalone catch plummeted and communities along the coast began to wonder whether they were going to lose their livelihoods.
“Like the surface of the moon”
Apart from a narrow band in the tropics, kelp grow well right around the world, hugging coastlines from the Arctic to the Antarctic.
There are more than 100 species – some which reach up to sixty metres tall and can grow two feet a day, while others cling to the shallows.
Kelp forests pull carbon from the atmosphere, protect the shore from erosion and improve water quality – and they provide habitat to countless marine animals, and livelihoods and food to the nearly billion of us who live within 50 kilometres of one.
“In a healthy kelp forest you have the diversity of fish and invertebrates, big and small, some the size of your thumbnail, some the size of you, living, feeding, breeding, being part of the ecosystem,” says UNSW kelp researcher Dr Aaron Eger.
But they are also under threat.
“We estimate that 65% of kelp coastlines are threatened and likely declining around the world.”
Alongside more than 200 researchers from 35 regions with kelp forests, Dr Eger has helped compile a first of its kind map of kelp conservation efforts worldwide.
Together, they are trying to show who is doing what and where, and what is working and why.
The details, published in the Journal of Applied Phycology , show a mixed bag.
“Kelp forests are declining in most regions, but there are a few regions that are stable, and then there are even a few that are increasing,” Dr Eger says.
But the study hints at some common threats, like rising ocean temperatures pushing some species past their limits, which the data shows can magnify other threats.
Booming sea-urchin populations are another key driver of decline, but the paper shows that an outbreak in one region might have different causes and different solutions to an outbreak in another.
“You might get new populations of sea urchins establishing when the water gets warmer,” says Dr Eger.
Or, as happened in the Pacific North-West of the United States, humans hunted otters nearly to extinction, and with nothing to eat them, urchin populations exploded.
“When we overexploit the big fish and predators that eat sea urchins, they end up really running rampant through a kelp forest.
“When the kelp goes it can feel like the surface of the moon down there,” Dr Eger says.
Bringing the kelp back
That’s certainly how John Minehan remembers urchin barrens, and it was a sight that compelled him to act.
In the early 2000s, the abalone industry in eastern Victoria determined that to save their livelihoods they would have to restore the kelp.
To do that, they would have to get rid of the urchins.
“We thought ‘this is the answer, this is all we have to do, and abalone production will stabilize and potentially grow,” John says.
Clearing the urchins was relatively straightforward.
An army of commercial divers headed out to the reefs and plucked the spiky purple-black invaders off the rocks one by one and tossed them into sacks.
Thousands of them, tens of thousands.
John says each diver could remove around 1800 urchins an hour, or around 5000 in a typical three-hour shift.
“That’s about two a second,” he says.
“We became quite efficient at it.”
At first, there were just so many urchins it didn’t feel like they were making much of a dent, but that soon changed.
“Very quickly when you go to swim around the reef, you realize ‘that area’s been cleared, and that area’s been done, and those divers have done over there’.
“As a team we were able to clear quite large areas quite quickly.”
And within about 18 months after they first started, the kelp was back.
From the seabed on up
Dr Eger’s paper shows that around the world different groups are tackling the decline of kelp in different ways.
Attempts to build community grassroots stewardship are common, and Dr Eger says that nearly everywhere you find kelp, you find researchers mapping and monitoring it.
“I’m reassured that everyone’s on it and working on it and is willing to participate in this,” he says.
But active restoration – planting kelp seedlings on areas of barren reef or removing urchins so kelp can return naturally – is taking place in less than half of regions.
That’s concerning to Dr Eger because while it means we have increasing data on the scale of the problem, we’re not always doing much to solve it.
“There’s sometimes this mentality of ‘collect more data, collect more data, collect more data’,” he says.
“We just need to start making conservation decisions before time runs out.”
The study notes that while ocean warming, marine heatwaves, and climate-driven ecosystem change are huge drivers of kelp decline, adaptation measures are not common.
Scientists in California are furthest ahead – they’re studying kelp genomes to identify heat-resistant species, information that could one day be used to restore forests.
But that’s a long way off being rolled out at scale and is anyway hamstrung by a lack of funding – a problem, the study notes, facing restoration efforts globally.
“Much of the world doesn’t really think about kelp decline,” Dr Eger says.
“And that’s cool because it’s led to these more grassroots, underdog type organisations working on the problem just because they love it, not because it’s the most attractive thing to do.
“If we can just get these groups the support they need, there is an incredible potential to unlock some truly positive change for our oceans.”
Dr Eger hopes that the Kelp Forest Alliance can unify the disparate groups working to save kelp – scientists, commercial fishers, Indigenous Groups and volunteers – in a global network that shares data and expertise and drives conservation forward.
“The fact that we got this group together is really empowering to me,” he says.
Where did the abalone go?
It’s been nearly a decade since kelp restoration wrapped up off eastern Vic and John says the kelp forests are still healthy, as are the communities that rely on them.
They managed to restore about 100 hectares of kelp in all, and when juvenile abalone were spotted re-colonising the reefs, locals began to celebrate.
“In every instance there’s an initial response,” John says.
“They grow and move around and migrate onto the areas that have new kelp on them.
“I guess maybe the fresh kelp is sweeter tasting? Who knows.”
It felt promising, like their plan had worked and that all the money the community had tipped into the largely self-funded restoration program had been worth it.
But that initial response soon fizzled.
No one knows why, but the thick and healthy kelp cover hasn’t meant an increased abalone catch, and populations aren’t recovering.
“It’s deeply disheartening,” John says.
“The size of our harvests continues to drop, and the economics of our industry has suffered as a result.”
But John and the abalone divers have adapted.
When they first started clearing the sea urchins they saw them as nothing more than an invasive pest that needed to go.
In the years since though, a whole new industry has popped up along the coast, an industry that might ensure the future of the kelp after all.
You can eat sea urchins – the Japanese call it “uni”, the Italians “ricci di mare”, and the Chileans simply say “erizo”.
The delicate, salty-sweet flesh hidden behind those brittle spines has the texture of custard and is prized for its richness.
There are now multiple businesses in the Mallacoota area processing sea urchins for export, something that never existed before.
John credits the new industry to the durability of the kelp’s return, saying that because they’re out there collecting them, sea urchins aren’t getting to plague proportions.
“It’s employing more people in these small regional towns, and the urchin harvest alone improves the kelp forest.
“The urchins at one point felt like the enemy, but it turned out that they had real value and ultimately became a much larger industry.”
He’s backed up by Dr Eger’s study, which points to an emerging model of restoration that is making a huge difference.
From British Columbia to Mexico, all the way over to Japan and down to Mallacoota, kelp is thriving where it’s linked to people who have a long-term economic stake in its health.
It’s not the whole solution, but it shows a way forward.
“We have the capacity. It’s just a matter now of redirecting that knowledge and putting it into action,” Dr Eger says.
“Now that conservationists have a sense of what can work, they need to get on with it.”
