California Kelp Forests Rebound After Removal of Millions of Urchins
Santa Barbara, CA – A large-scale restoration project in California has demonstrated remarkable success in reviving decimated kelp forests, offering a potential blueprint for similar efforts worldwide. By removing 5.6 million purple sea urchins, the project spearheaded by the Reef-Check Foundation and partners, has allowed kelp to regrow and ecosystems to recover along a meaningful stretch of coastline.
For decades, California’s kelp forests – vital underwater ecosystems providing habitat for a diverse range of marine life – have been ravaged by an explosion in the purple sea urchin population. these urchins, normally kept in check by predators, multiplied unchecked following a disease outbreak that decimated the sunflower star, a key urchin predator. The resulting “urchin barrens” left underwater landscapes stripped bare, threatening the health of the ocean and the livelihoods dependent on it.
the restoration effort, focused on areas off the coast of Santa barbara, involved divers manually removing the urchins. “Just starting to differentiate and grow the bulbs that keep the structure afloat,” Reef-Check Foundation’s Steve Ford described the kelp’s recovery, noting its rapid growth, “Even as a parent to fast-growing children, it’s hard to imagine the speed at which this algae moves – always upward, always out.’Everything flows from the kelp.'”
The restored sites have proven resilient, and are showing significant ecological improvements.Research from the foundation indicates the return of California spiny lobster to the area, and increased abundance of fish like kelp bass and sheepshead compared to pre-restoration levels. The kelp also improves water quality by absorbing excess nutrients and stabilizing sediments. Notably, the valuable red sea urchin population has also benefited, with gonads (uni) weighing 168% more in restored areas.
While warmer ocean temperatures, exacerbated by climate change, continue to pose a threat, the project offers a hopeful outlook. Similar kelp restoration initiatives are underway in Tasmania, South Korea, and are planned for California’s Santa Barbara channel. Ford emphasizes the inherent resilience of kelp, stating, “Part of the reason why we see such a rapid response to the restoration is as the system has evolved to respond rapidly to beneficial conditions.”
