Fighting the Tide: Efforts to Restore the California Kelp Forest

(Photo courtesy of NOAA’s National Ocean Service)

As climate change continues to transform our planet, many of its effects are fairly visible to us – things that make the nightly news, like fires, floods, heat waves and hurricanes. But we sometimes forget that climate change touches every part of our planet. Scott Baba filed this report, on the vast but mostly unseen changes happening in our own (underwater) backyard.


By Scott Baba ([email protected])

PACIFICA, CA – From the shore and to the casual eye, the California coast looks like a healthy ecosystem. But what’s under the waves is a different story. Not just in one place, but almost anywhere you go in the state.

Under the surface, and just a short way out, is an entire ecosystem that most people never see: California’s kelp forests. Like their land counterparts, they have thick canopies on the surface and layers in the water beneath. The kelp is tall, sometimes up to 90 feet from ocean floor to surface.

Seen from below, it almost looks like a kelp cathedral. The kelp rises in leafy columns, and it’s mostly dark except where a stray sunbeam pierces the water.

These kelp forests are incredibly important places for biodiversity. The kelp, which can grow up to two feet a day, is a food source for many undersea animals.

Kelp forests support a wide range of species of fish, invertebrates, birds and marine mammals, and they offer safety for creatures that hide among the stalks.

In these underwater biomes you can find California’s state fish, the bright orange garibaldi. Seals and sea lions play in them. Sea otters need them to thrive. They are one of the world’s most productive ecosystems.

And over the last eight years, they have all but disappeared.

Where once there were rich underwater forests, teeming with life, now, in most places, there is nothing but bare rock carpeted in spiny purple urchins. In fact, the Northern California coast has lost more than 95% of its kelp forests in the last eight years.


Joshua Smith is a Ph.D candidate at UC Santa Cruz, where he studies different sea species. He started in 2012, right before the collapse of California’s kelp forests. Smith said that at the time, the kelp forest was thriving.

“I remember going out in Monterey Bay to do dive surveys,” said Smith. “In many places the kelp had grown all the way to the surface of the ocean and it had spread out so dense at the surface that we couldn’t even get our dive boat into the place where we needed to do our surveys. I mean, there was just a lot of kelp in 2012. And shortly after that, though, in the year 2013 is when things began to rapidly change.

The change in 2013 actually had very little to do with the kelp itself. But it shows just how interconnected the ocean really is. And it starts with an animal you may have encountered at the beach – the sea star.

Starting that year, the western coast of North America was hit with a catastrophic wasting disorder that decimated sea stars populations up and down the coast.

The leg of this purple ochre sea star in Oregon is disintegrating, as it dies from sea star wasting syndrome. (Photo by Elizabeth Cerny-Chipman, courtesy of Oregon State University)

When sea stars get the wasting disease, they die over days or weeks. Their arms twist grotesquely. They develop lesions over their bodies. Their limbs deflate, stretch like taffy, and fall off. Eventually, they melt away completely.

Sea star wasting syndrome isn’t a new phenomenon. California had multiple outbreaks between the 1970s and the 1990s. But those events pale in comparison to the one that began in 2013. That event hit roughly 20 species of sea star from Baja California to the Northern Gulf of Alaska. It pushed some to the brink of extinction.

Scientists aren’t sure what causes it, but they know it’s exacerbated by warming water. Smith said the loss of the sea stars threw the environment out of balance. Especially one species called the Sunflower Star.

“This is a sea star that can grow to be about the size of an extra large pizza,” Smith said. “They have over 20 arms and they just cruise around the reef eating just about everything. But they’re predators, so they eat all sorts of things. They eat snails, other molluscs, and they especially like to eat sea urchins — and sea urchins are the other key player in this story.”

Sea urchins are spiky sea creatures that live on the ocean floor. They look like small purple hedgehogs rolled tight into a ball and covered in bristling spines. More than anything they love to eat kelp.

Found along the Eastern Pacific, this photo was taken in the intertidal zone of Willows Beach – Santa Cruz Island, CA. (Photo courtesy of Gregory Smith)

Once the sea star wasting disease hit, the urchins no longer had one of their key predators

Fewer sea stars eating urchins meant a lot more urchins eating kelp. And then, on the heels of that event, one of the worst marine heat waves ever recorded hit the pacific coast in 2014.

Dubbed “the blob,” the marine heat wave filled the north Pacific and blanketed a thousand miles of coast with warm water. It raised the ocean temperature an average of seven degrees Fahrenheit. It wreaked havoc on the ocean and decimated populations of fish, birds, and sea mammals. Many have yet to recover.

Scientists say the blob was likely caused by climate change, and that we’re likely to see more new ones – indeed we’ve actually already seen one since. As weather patterns shift, events like it could become the new normal. A second blob-sized heat wave struck in 2019.

While warm water doesn’t kill kelp, it carries far less nutrients than cold water, stunting the kelp’s growth. Smith said that, with fewer predators, the sea urchin population exploded. And with less kelp to go around, they spread far and wide in search of food.

“They started storming around the open reef, actively looking for any other kelp they could find and just a gobble up,” Smith said. “And so up and down the coast, from Mendocino and Sonoma down to the central coast of California, we saw these widespread sea urchin outbreaks where the urchins in many places had eaten everything, all of the kelp and the other macro-algae that attaches to the reef, the urchins had eaten. We call these places ‘sea urchin barrens,’ and underwater it just looks like a carpet of purple. And on the north coast of California, up in Mendocino and Sonoma, we saw hundreds of kilometers of total kelp deforestation.”

Jon Holcomb has seen this firsthand as well. He has been diving commercially for nearly half a century. He said he’s seen a lot of change in the kelp forests over the years.

“Over the last 30 years – in 33 years on the north coast – I’ve watched it come and go,” Holcomb said. “Some years, three, four or five years in a row, it’s just like a mat. You could walk across it. But there were areas the kelp didn’t come back in, and there were areas urchins didn’t come back in. You didn’t really notice except, you know, Jesus, another bad kelp year. And then when I swam in 2015, I was stunned to see what had happened.”

The hundreds of square miles of kelp forest along the coast hadn’t just come back weaker or come back smaller – it hadn’t come back at all. And in its place there was a nearly lifeless reef.


So looking at the scale of the problem, the question is: what do we do about it?

Climate change has already fundamentally altered the natural systems of the ocean, and its effects have compounded in California’s kelp forests in ways that seem difficult to address. Getting to this point wasn’t a simple matter. The way out – if there is one – won’t be either.

Scientists and divers have proposed a number of solutions to save the kelp forests.

Nancy Caruso is a marine biologist who spent 10 years rehabilitating giant kelp forests in Southern California before the current kelp forest collapse. Caruso said she and her team tried all sorts of things to get kelp back on the reefs.

“We grew the kelp on little pieces of bathroom tile,” said Caruso. “We also tried growing the kelp on ropes, on pieces of plastic.”

Caruso said that results were mixed and success was varied. Kelp is surprisingly finicky. It’s male and female spores need to find each other in the water. But they don’t travel very far. And the kelp won’t grow if the spores don’t land on the right kind of bed. Despite all this, she said they kept trying.

“These microscopic spores are swimming around,” Caruso said, “and we could take those spores and manipulate them, put them on whatever surfaces we wanted to so that we could grow them in these classroom laboratories and then take that kelp on the tile or the rope or the, whatever we put it on and out plant that in the ocean, tie it to the reforest, string it up until it gets bigger and starts to grow onto the reef naturally. And so it is kind of a process that starts off microscopic, and then a giant kelp can grow very quickly – up to two feet a day in ideal conditions. So once we would get it into the ocean, it would take off and grow gangbusters.”

Caruso said that after a decade of hard work, she and her team restored about 42 miles of coast.

On the one hand, that’s an incredible success. On the other hand, it brings home the disheartening scale of the problem – because California has lost hundreds of miles of kelp forest in the last few years.

Caruso now leads an environmental organization in Orange County called Get Inspired. Seeing what happened to Northern California kelp forests after 2013, she said she had to take action.

“Having spent 10 years of my life restoring kelp a decade earlier, I said, gosh, I know how to fix this. We need to act quickly because this is a different species of kelp up there.”

Caruso had worked with the giant kelp that grows in Southern California, not the Bull Kelp of the Northern California coast. Still, she said there were some basic tenets that held regardless of the species.

“I do know that if [the kelp] is gone for too long, those microscopic spores that I mentioned settle down on the rocks,” said Caruso, “and if there isn’t suitable habitat or there aren’t suitable conditions, they can wait for suitable conditions sometimes. But if you go too long, those small little sporophytes – or gametophytes at that stage – are going to die. And I don’t know how long that period is for the bull kelp that’s on the north coast, so I was very concerned, as once you lose the parents, it’s hard to make babies.”

Then she thought, maybe she ought to work on what was destroying the kelp in the first place: the sea urchin.

Caruso started organizing efforts in Northern California to gather and kill urchins.

“I don’t think anybody wants to quit. But it’s a daunting challenge, even to clear one cove.”

– Jon Holcomb, commercial urchin diver

She contacted Jon Holcomb, the diver of 50 years, and brought him on board. Holcomb already had a commercial urchin harvesting license and spent the summer of 2018 removing sea urchins in Caspar Cove in Northern California. He even adapted an underwater vacuum to suck up hundreds of pounds of urchins a day.

“We had to make a decision,” said Holcomb, “whether you’re going to try to do something about this or throw your hands up in the air and say, ‘Well, it’s over, you know, that’s it.’ And I don’t think anybody wants to quit. But it’s a daunting challenge, even to clear one cove. So we went to work in 2018 and removed 50 days worth the urchins, which was 35,000 lbs.”

You may be wondering whether it’s possible to sell or eat urchins, to make humans the new predator that might keep the sea urchins in check. In fact, before the kelp forests disappeared, Jon Holcolmb made his living diving for red sea urchins, considered a delicacy by some.

Unfortunately, it turns out it’s not a profitable venture. Most of the urchins swarming the California coast are the less tasty purple urchins, not the red urchins. And when urchins starve, they consume their own gonads, which is the part that people eat.

Holcomb said divers can’t make money off the empty urchins, so the urchin removal work has been inconsistent due to lack of funding. Still, he said that he wants to continue the work to help the kelp.

“Your ocean’s basically toast if we don’t get the kelp back for our coastal fisheries,” Holcomb said. “It all lives one way or another off the kelp. little fish grow up in the kelp; bigger fish come in and eat them; bigger fish come in like salmon and tuna eat them and the seals eat them. The sea birds eat kelp flies, stuff you wouldn’t even think about – I mean, it’s part of the food chain for the birds.”


But if commercial purple urchin fishing isn’t taking off anytime soon, maybe there’s another way – relying on recreational divers who want to help.

Keith Rootsaert is a diver, and the founder of the Giant Giant Kelp Restoration Project. He’s been working to get recreational divers to help with the sea urchin problem.

Rootseart said that he spent years trying to convince the California fish and game commission to let divers cull urchins around Monterey.

“We tried it in 2017, they told us no. We tried it in 2019, they said no,” said Rootsaert. “And then in 2020, I tried it again, and I was told no. But this time I brought everybody – I just brought all the diving community, and everybody wrote letters, and we sent like 260 letters to the commissioners. And we had times when we would go to these meetings and we weren’t even on the agenda; we would take an hour of their time at general comments, just talking about urchins. And eventually they said yes.”

With the Commission’s blessing, Rootsaert partnered with the ocean restoration group Reef Check to set up a pilot site near Monterey last year. They train recreational divers to go out, find urchins and smash them with hammers on the spot – like eggs.

“We have set up this underwater grid from Reef Check that is a hundred meters by a hundred meters,” said Rootsaert, “so that’s a pretty good size. It’s two and a half acres basically that is being very closely monitored with lanes on it. You can swim down these lanes and cull the urchins. That way we can tell what the urchins are able to be reduced to by diver efforts.”

Rootsaert said he hoped the pilot program will prove that a volunteer effort can make a difference.

“It’s really kind of an experiment to determine if this is something that is a useful tool for combating kelp loss,” Rootsaert said. “Make kelp restoration something that’s in the Fish and Wildlife Department’s repertoire of tools – and they could use recreational divers as part of that solution.


Joshua Smith, the UC Santa Cruz PhD candidate, said that while there are some encouraging results from urchin culling programs, there are also some big caveats.

“It’s important to think about that method in the bigger scale of what’s going on,” said Smith.”On the north coast of California, it’s hundreds of kilometers of coastline that have been deforested and there’s urchins everywhere. And so you can imagine how difficult it would be to really remove enough urchins.”

Especially one at a time, by hand, with volunteer divers on oxygen. And clearing a reef of urchins just once won’t be enough.

“It seems that in order for it to be effective, it’s a long-term commitment,” Smith said. “It’s something that has to be done repeatedly, for a very long time.”

So is there a more permanent solution than going around the seafloor, finding and smashing sea urchins?

Smith said that this could actually be a problem nature might have to solve for itself.

Unfortunately, starving urchins don’t die. They go into a state of dormancy and can sit on the ocean floor for years or decades, hungry and empty, waiting for food to return. Still, there are other natural events that might clear them out.

Surprisingly, that might look a lot like something that started the kelp forest collapse in the first place – a disease, but one infecting the sea urchins instead of the sea stars.

According to Smith, this is something that could be lightning fast. In the same way the sea stars were decimated in a single year, something similar could happen with urchins.

“Anytime you have a lot of individuals living in close proximity and warm water together, those are kind of a recipe for disease,” said Smith.

We may just have to wait for a disease to wipe out the urchins so the kelp can come back.

Smith said that, based on what we know about the way that disease moves through populations, such a disease could be catastrophic.

“If the conditions were right, such that a disease were to move through the urchin population, it could happen really fast,” Smith said. “It could wipe out a ton of urchins, and kelp could recover next year.”


If sea urchin disease is really the best shot we’ve got, what about all the efforts by divers and scientists?

Some of it does seem to be working. A partnership between Reef Check and commercial fishermen over the last year in Mendocino County cleared out enough urchins to let bull kelp start growing back.

At the same time, the basic arithmetic of urchins plus starfish plus heat waves hasn’t changed. And conservationists still aren’t sure how to scale up from a few acres to an entire continental coastline.

Still, Nancy Caruso, for one, isn’t planning to stop looking for solutions.

“We have to keep trying,” Caruso said. “How many times did we blow up rockets trying to go to the moon? uh, so that’s basically the foundation of science is, yeah, we don’t see how this is going to work for the entire coast, but maybe we’ll find it. and in the meantime, we’ll keep plugging away.”

Others say the current exploitative relationship to the ocean needs to change – from extraction to stewardship. For Rootsaert, the work he’s doing now is just the first step.

“This is not a problem that we’re going to solve and then we’ll all pat ourselves on the back and say, ‘Well, that’s great, let’s go back to diving now,’” said Rootsaert. “This is going to become the new ocean. We’re going to have to provide ecosystem services to it. It’s just how it’s going to have to be.”

Rootsaert said that it wasn’t enough to simply observe and study ecological disasters without acting anymore.

“Everyone’s just watching it, and they’re counting urchins with their fingers – and I want to count urchins with a hammer,” Rootsaert said. “I want to get something done and change everyone’s opinion of whether this can be done or not. Let this be a tipping point in California ecological history.”


For Rootsaert and many others interviewed for this story, it is no longer enough for us to just take from the ocean. It may now be our responsibility to actively nurture and maintain it.

As climate change progresses, we face a new “new normal” every day. The collapse of the kelp forests happened at the intersection of extreme events. But extreme events are more and more common, pulling apart the delicate web of interactions that make up ecosystems.

We don’t know how effective these efforts will be in the long run, or whether they can be scaled up to save more than a single cove or beach or small stretch of coast. Either way, the truth is, right now we’re witnessing what happens when something as vast and timeless as the ocean is being so damaged by humans under our watch.


This story was produced as a part of the KPFA Storytelling Project. In addition to those voices you heard in the story, special thanks to Joshua Russo, Tom Ford, Mitchell Masuda, and James Price. This story was edited by Lucy Kang with support from Ariel Boone and produced by Scott Baba. Music by Blue Dot Sessions.