Like the grey wolves that famously changed the ecology of Yellowstone National Park when reintroduced in 1995, sea otters are a keystone species. This is because they eat sea urchins and help to maintain balance in the kelp ecosystem.
Without otters around to keep the spiny marine animals in check, sea urchins will mow down kelp forests and create a kind of wasteland called an “urchin barren.” This is happening at an alarming rate off the Oregon coast. A count done in 2019 found 350 million purple sea urchins in one Oregon reef alone, which is a more than 10,000 percent increase since 2014. This situation is made worse by climate change as sunflower sea stars, the other natural predator of the purple sea urchin, died in droves from a disease made worse by warming waters, leaving kelp defenseless.
Without kelp, many fish and sea creatures are left without shelter and habitat, and species like sea urchins, crabs and other marine life are left without their primary food source. Kelp forests are also critically important for our ability to tackle climate change because they, like many other coastal ecosystems, help keep carbon out of the atmosphere.
Every day without sea otters is another day of an ecosystem out of balance-- one that is biologically poorer, less resilient and less helpful in our fight against climate change.