Sonoma’s kelp forests vanished – scientists just discovered why

An international team of scientists recently announced a major breakthrough in understanding sea star wasting disease, a mysterious epidemic responsible for decimating sunflower sea stars. More than 90% of this crucial species has vanished from California’s coastline since 2013, significantly affecting Sonoma County’s marine ecosystems. Researchers identified the bacterium Vibrio pectenicida as the disease’s culprit, potentially opening the door to recovery efforts.

Sunflower sea stars once played a key role in controlling purple sea urchin populations, protecting the kelp forests along Sonoma and Mendocino counties’ coasts. With this predator nearly extinct, purple urchins multiplied dramatically, destroying over 95% of the region’s kelp forest cover. Formerly thriving areas such as Ocean Cove have been transformed into barren underwater landscapes.

The collapse of kelp forests severely impacted local biodiversity and economy. Abalone and commercial red urchin populations faced devastating declines. NOAA Fisheries estimated an annual economic loss of $44 million after the closure of the recreational abalone fishery. The crisis has deeply affected local divers, fisheries, and related businesses.

In response, the Sonoma-Mendocino Kelp Recovery Plan has mobilized local scientists, divers, and stakeholders. Restoration efforts include divers removing thousands of pounds of urchins at locations like Timber Cove, significantly aiding kelp habitat recovery. Additionally, institutions such as the California Academy of Sciences have initiated captive breeding programs aimed at reintroducing sunflower sea stars.