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Eat sea urchins to save the oceans

These spiny little animals are in desperate need of population control, and our sushi habits could help.

‘Eat more seafood to save the oceans' is not a message we hear much these days, but when it comes to one particular species, it might just work. Sea urchins are notoriously hungry creatures that ravage kelp forests when their natural predators disappear, due to overfishing, warming waters, pollution, or a tsunami. Once the kelp forests have been consumed, the urchins starve but remain alive in stasis for years, their shells empty and unappealing to predators, but still preventing the kelp's regeneration. The resulting ‘urchin barrens' are essentially underwater deserts, where nothing grows and no other fish species can live.

Enter an innovative company called Urchinomics. It collects these empty yet living urchins and relocates them to an underwater ranch, where they're fed a specially formulated feed made from Japanese kombu (also kelp, taken from places with an overabundance or sustainably farmed). The feed is 100 percent natural and plant-based, with no corn, soy, antibiotics, growth hormones, or fishmeal added. The urchins fatten up in 4-10 weeks, depending on conditions, and are then harvested for human consumption. Even more impressive is how little feed it takes to grow urchins – a mere 0.4 kg to produce 1 kg of roe. Compare that to the 28 kg of feed required to produce 1 kg of farmed bluefin tuna, or 6 kg for beef.

Diver collects urchins© Urchinomics

Urchin roe, known as ‘uni' in Japanese, is popular among sushi lovers. Urchinomics describes it as having “a buttery, sweet and briny flavor with a creamy rich gold consistency. Connoisseurs of milder caviars will find a strong similarity.” Bon Appétit named it a top food trend in 2018, saying it's gone from being an acquired taste to being everywhere. The flavor is affected by what the urchin eats, which is why Urchinomics has opted for Japanese kombu in the feed, to maximize the desirable “umami” taste.

It only takes two urchins per square meter of ocean floor to cause desertification (many places in California, Japan, and Norway have 20+ urchins per square meter); but once removed a kelp forest can regenerate rapidly. Within three months, a forest will return with all its carbon-sequestering benefits, “essentially binding atmospheric carbon that is dissolved in the oceans and turning it into the blades, stems and the holdfast that keeps the kelp firmly rooted on the ocean floor.” Predatory species, such as crabs, fish, and sea otters, will return and eat the urchins and their larvae, helping to keep populations under control. Their presence inhibits more urchins from moving up into the kelp forests from deeper waters.

urchins in a tank© Urchinomics

Urchinomics says it can offer consistency in a market that, traditionally, has been full of unknowns. “Perfect wild urchins, bitter and discolored urchins, empty barren urchins and carefully ranched urchins all look the same and weigh more or less the same, making it notoriously difficult for buyers and sellers to agree on prices when the quality and quantity of roe is one big guessing game.” Ranched urchins, by contrast, have reliable color, taste, consistency, and harvest quantities.

It sounds like a win-win situation all around, and it will be interesting to see if Urchinomics‘ ambitious project pays off.

These spiny little animals are in desperate need of population control, and our sushi habits could help.