Meet the delicious purple sea creature destroying Pacific kelp forests

By Francisca Benitez (OPB)
June 17, 2021 12 p.m.

Few things unite Pacific Northwest culture, economy and ecology like food. And at the center of the Northwest food scene are the ingredients themselves. Home to hundreds of commercial crops and edible bounty, this region is a gastronomic powerhouse of diverse, essential and surprising foods.

Where do these ingredients come from? What communities do they support? What makes them delicious? And what can they become in the hands of the best food makers in the region? “Superabundant” is Oregon Public Broadcasting’s new video series dedicated to the stories behind the foods you love.


Hundreds of millions of brainless purple sea creatures are attacking the delicate ecosystem of the West Coast. Purple sea urchin population is up 10,000% in recent years, and they pose a serious risk to kelp forests. They’re also delicious.

Underwater aliens

Purple sea urchins are recognizable by their spiny bodies and deep purple color. They have retractable tube-like arms that pop up through their sharp spines.

“Those spines come in handy, because they sit in these little crevices and they just wait for kelp to drift by and get snagged on their spines. And then they reach up and grab it and move it down to their mouth, which is on the bottom of their body instead of the top,” said Tom Calvanese.

Calvanese is the Oregon State University Port Orford field station manager. He worked as a commercial urchin diver when he was a student, and is now a fishery scientist.

Sea urchins are echinoderms, like sea stars, sand dollars and sea cucumbers. Like other echinoderms, urchins have five body segments — arrayed in a pattern known as pentaradial symmetry. Inside their spiny outer shells they have five reproductive organs, called gonads.

“So yeah, these urchins have five ‘nads, as the kids like to say. And, that’s pretty weird,” Calvanese said.

Tom Calvanese harvests purple urchins.

Tom Calvanese harvests purple urchins.

Stephani Gordon / OPB

These organs are used by male and female urchins alike to broadcast sperm and eggs, respectively, into the water to reproduce. After a few weeks, tiny urchins are created. The babies find shelter under the spine canopy of adult urchins.

“They have this sort of intergenerational relationship where those adults are creating a shelter for the little tiny baby urchins,” Calvanese said.

Urchins eat kelp, and with their population absolutely exploding along the West Coast, their destruction of the kelp forests has been described as “underwater annihilation.”

An unbalanced ecosystem

We’re talking about hundreds of millions of urchins that live for decades and are resistant to predators thanks to their spines.

Purple urchins used to have two natural predators: otters and sunflower sea stars.

“Imagine if that otter had been there when this started to unfold, it may have been able to play a role in sort of defending the kelp forest from all these urchins that were coming in. We don’t know, because we didn’t get to have that experience,” Calvanese said.

The population of wild otters was decimated long ago by fur trappers. The sunflower sea star population has been a victim of disease, likely due to climate change.

Without the predators keeping the sea urchins in check, their population has increased 10,000% in recent years. They are devastating kelp forests, which serve as an important habitat and food source for many organisms in the ocean ecosystem.

But there is another natural predator of the sea urchin — humans. Sea urchin is a popular dish at sushi restaurants, where it’s called uni.

Chef Christian Gomez prepares uni at The Nest Cafe.

Chef Christian Gomez prepares uni at The Nest Cafe.

Stephani Gordon / OPB


“When you go to the sushi bar and you order uni, what you’re ordering is a sea urchin gonad,” Calvanese said.

Red sea urchins, a cousin of the purple variety, are already harvested and eaten on the West Coast, but the purple ones were once considered too small.

“The urchin divers really got this started in the beginning. They started to see the problem and they started to develop a market for purple sea urchins,” Calvanese said. Now, purple urchins are being captured and raised in tanks to mature, turning an invasive species into a delicacy.

People eat the purple kelp eaters

“I was particularly fascinated by the fact that you could cook something and make a difference by doing that,” Jacob Harth said. Harth is a renowned Portland chef who created a drive-in clam shack pop-up on the coast in Tillamook, Oregon.

On the menu at the pop up shop is uni toast, a dish Harth created.

One way to serve sea urchin: on toast.

One way to serve sea urchin: on toast.

Stephani Gordon / OPB

“I think it just is a shining example of a potential for what chefs can accomplish by making different choices about what they want to put on their menu,” he said.

The dish is made with a local slice of sourdough bread, griddled and then slathered with house-made butter. The uni is placed on the toast and topped with sauce.

“The sauce is made with egg yolks and a sort of a white soy sauce tamari that’s made from a miso that we make with Dutch bullet beans. And then we just thicken that with the egg yolk and spoon it over the top,” Harth said.

It doesn’t hurt that the uni is delicious.

“I love sea urchin,” Harth said. “It’s one of my favorite things to eat in any food category, but especially seafood, especially when you’re taking them right out of the water like that.”

“They have a wonderful complexity and they’re almost seasoned to the point of just being ready to eat on their own,” he said.

“When the uni quality is good, it’s like nothing else,” Calvanese said. “It definitely has a taste of the sea, of course, but it’s got this buttery unctuousness, if that’s a word. It’s just so yummy.”

Christian Gomez of Nest Cafe is another chef innovating with purple sea urchin. He created an uni carbonara topped with uni foam.

“When my brain thought of uni or utilizing uni, I compared it to eggs and butter. Because that’s the creamy aspect of it. And it kind of feels, texture-wise, like a sea cow tongue, but it breaks down really quick and it’s super fatty,” he said.

Sea urchin served with pasta.

Sea urchin served with pasta.

Stephani Gordon / OPB

Although serving up the urchins will not completely solve the challenge of overpopulation, it’s not often that patrons of restaurants get the opportunity to literally take a bite out of an environmental problem.

“We have this complicated problem, we are going to come at it from many different angles,” Calvanese said. “Scientists are going to study it, resource managers are going to be partners in this, divers, eco-tour operators are going to take people out there and educate them about it, and then also chefs,” he said.

“I think that the chef’s role is super important because that’s how the market for it starts on the consumer level,” Harth said.

Few things unite the Pacific Northwest’s culture, economy and ecology like food. And at the heart of everything “foodie” are the ingredients themselves. Home to hundreds of commercial food crops and products, Oregon is among the most diverse agricultural producers in the nation, if not the world. Where do these ingredients come from? Who grows them? What communities do they support? What makes them delicious? And what can they become in the hands of the best chefs in the region? “Superabundant” is OPB’s video series dedicated to the stories behind the foods you love.

Related: Watch all episodes of "Superabundant" here


Tags: Food, Oregon, Culture