Land-based sea urchin ranchers are kelp forest crusaders and sushi entrepreneurs

Oregon’s OoNee Sea Urchin Ranch is ramping up its land-based sea urchin farm using RAS technology

Often likened to cockroaches, zombies and sheep, sea urchin populations have gotten out of balance within ecosystems along the West Coast of the United States and some coastal areas of eastern Asia. As a result, the spiky critters can clear-cut a kelp forest, leaving hundreds of dormant sea urchins to litter the ocean floor, lying in wait to attack any regrowth.

When healthy, those sea urchins can yield tender uni, the urchin’s bright orange gonads that are widely used in sushi. The global market for sushi was $5.85 billion in 2024 and will reach $10.76 billion in 2033, a compound annual growth rate of 7.92 percent, according to Business Research Insights, with uni occupying expensive areas of sushi menus worldwide. Startup OoNee Sea Urchin Ranch aims to apply new technology and techniques to the production of purple sea urchins, thereby tapping into the growing sushi market and helping to restore ecological balance.

“We are pulling overpopulated sea urchins out of the southern Oregon reefs,” CEO Aaron Huang told the Advocate. “We are bringing those empty, starved urchins onto a land-based ranch, fattening them up and selling them regionally and hopefully nationally and globally over the next few years.”

OoNee is currently developing a prototype modular ranching unit that will fit inside a shipping container. The output of the 25-foot raceways in the unit will be six vintages a year of commercial sushi-grade uni. The total yearly production will be in the tens of thousands of grams, with a wholesale price of $80 to $150 for 200-gram portions. The math works out to a complete payback of the expected cost of a ranching module within a couple of years, according to Huang.

Moreover, the container can be completely detached from the sea because it incorporates a RAS (recirculating aquaculture system). Thus, there’s no need to get a permit along the coast, which can be difficult to obtain, and there’s less variability in the water with a fully controlled system. Having processing within a container means that the production facility can be near the consumer, with one possibility being something like a sushi restaurant located in a place like Las Vegas. Thus, the product will be both fresh and organic, without the need for preservatives and long-distance shipping, Huang noted.

The problem of sea urchin overpopulation along the U.S. West Coast began a decade ago when a surge of very warm water led to a double or perhaps even a triple whammy, said Luke Gardner, CA Sea Grant Aquaculture Specialist with Moss Landing Marine Laboratories. The rise in water temperature increased the impact of a wasting disease on sunflower sea stars.

“The wasting disease resulted in them pretty much all but going extinct here in California,” Gardner said.

Can ranching ‘zombie urchins’ boost uni, save kelp forests?

That wipeout of a natural predator of sea urchins took place as the warm water hindered kelp reproduction. On top of that came a bumper crop of sea urchins.

Sea urchins are the “sheep of the sea” because they’ll eat everything, although they prefer kelp. A boom in sea urchins can cause a clear-cutting of kelp and the rise of urchin barrens. Once formed, these denuded areas can persist for 100 years or more, Gardner said.

Part of the reason for the longevity of kelp-free regions is that urchins are also known as the zombies or cockroaches of the sea – it takes a lot to kill them.

“Sea urchins are as tough as nails,” Gardner noted. “They can be out there for years, starving or existing on very little food.”

In a dormant state, sea urchins only spring to life when they sense kelp or another food source. Economically, zombie sea urchins are worthless, as they lack the gonads used to produce uni.

Feed them, though, and the situation changes because they’ll grow what’s needed. That’s where OoNee Sea Ranch comes in. Huang noted that a diver with the appropriate skills and tools can pull about 1,000 pounds of sea urchins a day out of the water. Developing a market for dormant sea urchins would mean that divers would have an economic incentive to harvest them, thereby lessening the pressure on the remaining kelp forests.

Harvesting the sea urchins requires care because breaking any of the spines that dot the outside of an animal may lead to infection and death. Huang said that with the right precautions, sea urchin losses can be less than 10 percent during transport.

As for the future, along with other research Gardner investigates, such aquaculture-related aspects as what’s the best feed formulation for sea urchins. To be successful, a farmed product ideally must be as good as the wild variety in terms of quality, he noted. Gardner added that it’s possible a farmed product might be more consistent, which could increase the amount of uni deemed the highest quality.

For its part, OoNee plans to finalize its prototype container unit, field-test it and prove its profitability, a key requirement. “If you want to build something sustainably, you have to get it to cash flow positive as quickly as you can,” Huang said.

After that, the next steps could include licensing the technology to other entities, he added.

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