How Purple Sea Urchins are Taking Over California's Coastal Waters

Certain circumstances in the ocean can lead to "urchin barrens," where urchins dominate the ocean floor and mow down kelp forests. And without kelp, abalone are left to starve. But while urchin barrens may seem like a win for the species, the imbalance eventually leaves them malnourished. A healthy balance of diverse species is essential to thriving near-shore ecosystems.