Sea urchin explosion off California, Oregon decimates kelp

Tens of millions of voracious purple sea urchins that have alrey chomped ir way through towering underwater kelp forests in California are spreing rth to Oregon, sending delicate marine ecosystem off shore into such disarray that or critical species are starving to death.

A recent count found 350 million purple sea urchins on one Oregon reef alone — a more than 10,000% increase since 2014. And in rrn California, 90% of giant bull kelp forests have been devoured by urchins, perhaps never to return.

Vast “urchin barrens” — stretches of denuded seafloor dotted with thing but hundreds of spiny orbs — have spre to coastal Oregon, where kelp forests were once so thick it was impossible to navigate some areas by boat.

underwater annihilation is killing off important fisheries for red abalone and red sea urchins and creating such havoc that scientists in California are partnering with a private business to collect over-abundant purple urchins and “ranch” m in a controlled environment for ultimate sale to a global seafood market.

“We’re in uncharted territory,” said Scott Groth, a shellfish scientist with Oregon Department of Fish and Wildlife. “You can’t just go out and smash m. re’s too many. I don’t kw what we can do.”

explosion of purple sea urchins is latest symptom of a Pacific rthwest marine ecosystem that’s out of whack.

Kelp has been struggling because of warmer-than-usual waters in Pacific Ocean. And, in 2013, a mysterious disease began wiping out tens of millions of starfish, including a species called sunflower sea star that is only real predator of ultra-hardy purple urchin. Around same time, purple urchins h two excellent breeding years — and with predators, those gametes grew up and are w eating everything in sight.

“You can imagine all of se small urchins growing up, each one of m looking for food, desperate for food. y’re literally starving out re,” said Steven Rumrill, le shellfish expert at Oregon’s wildlife ncy. “I’ve seen some big-scale fluctuations in populations of sea stars and urchins, but never on this magnitude.”

Scientists aren’t yet sure if climate change is responsible for sea urchin explosion, but y suspect it plays a role in casce of events that allowed purple urchins to boom. And kelp, alrey under siege from warming waters, is t as resilient as it once was, said rah Eddy, an associate director at Nature Conservancy California’s oceans program.

“We’re going to see climate change as a big driver of changes in kelp forest as we move forward, and we are alrey seeing that,” said Eddy, who is leing an effort to use drones to map and monitor rrn California’s last remaining kelp forests.

devastation is also ecomic: Until w, red abalone and red sea urchins, a larger and meatier species of urchin, supported a thriving commercial fishery in both states. But 96% of red abalone have disappeared from California’s rrn coast as number of purple sea urchins increased sixfold, according to a study released this week by University of California, Davis.

Last year, California closed its red abalone fishery, which poured an estimated $44 million into coastal ecomy per year, and Oregon suspended permits for its 300 abalone divers for three years. commercial harvest of red sea urchins in California and Oregon also has taken a massive hit.

“That’s a huge ecomic loss for our small coastal communities,” said Cynthia Catton, a research associate with University of California, Davis Bodega Marine Lab. “In California, re were 30,000 to 40,000 participants in ( abalone) fishery every year for deces, and for first time ever that fishery h to close.”

And while purple urchins have eaten mselves into starvation as well, unlike or kelp-dependent creatures, species can go into a dormant state, stop reproducing and live for years with food.

That means only way to restore kelp is to remove or destroy purple urchins. Scientists estimate that in Oregon alone, it would take 15 to 20 years to remove all 100 million pounds (45 million kilograms) of purple urchins recently surveyed on just one large reef.

While urchins are in starvation mode, edible part — kwn as roe — shrivels, making m commercially worthless.

Against this backdrop, conservationists, commercial urchin harvesters, scientists and private interests are coming toger with an unusual plan: Pay underemployed red sea urchin divers to collect shriveled, but living, purple sea urchins and transfer m to carefully tended urchin “ranches” to be fattened up for sale to seafood markets around world.

One company, Urchimics, is alrey working on urchin ranching projects in Japan, Cana and California and sees a future where overwhelming demand for wild urchin roe is replaced by a taste for human-raised purple urchins collected from seafloor, allowing kelp forests to rebound.

“We’re turning an ecological problem into an ecological opportunity and an ecomic opportunity,” said Brian Takeda, Urchimics CEO. “It’s first time we’ve ever h an ecomic incentive to get se destructive urchins out of water.”

In Oregon, red urchin divers are a tiny artisanal collective, but y are also exploring ways to try to turn glut of destructive purple urchins to ir vant. Oregon’s urchin fishery h a boom year last year when red urchins were scarce in California but before ir purple cousins h spre rth. w, y too are hurting.

Rumrill, shellfish expert from Oregon, supports efforts to harvest excess urchins but strikes a less optimistic te when it comes to saving kelp.

“That’s a promising technique. But we shouldn’t fool ourselves into thinking that we’re going to solve this large-scale ecological problem, this literal perfect storm of events, by eating our way out,” he said. “It’s just too big a problem.”