Sea urchin population explosions following sea otter and predator decline create urchin barrens that devastate kelp forest ecosystems and affect all dependent species.
Kelp forest collapse from urchin overgrazing harms the welfare of the diverse fish and invertebrate communities that depend on kelp habitat for food, shelter, and reproduction. Fish displaced from collapsed kelp forests face increased predation exposure and reduced food availability. Restoring predator control of urchin populations through sea otter reintroduction and predator recovery represents both an ecosystem restoration and welfare benefit.