Kelp Restoration: The Process
Kelp Loss | Sea Urchin Barrens | The Process
Site Selection
Kelp is being restored in Fort Ross Cove, Timber Cove and Ocean Cove (map). Sites were selected from historical persistence of kelp canopy, subtidal ecology assessments and for their accessibility. The subtidal ecology at these sites were assessed in 2021 and 2022 including the density levels of sea urchins.
Drone surveys of kelp canopy help determine kelp refuges, where some kelp forests still persisted, that can be seen as dark patches in the water from above. Below is the kelp refuge at Timber Cove.
Aerial photo (right) of remnant kelp in Timber Cove by Abby Nickels, GFA.
Reducing sea urchin grazing pressure
Since 2023 far, over 35,000 lbs of urchins have been removed from Fort Ross Cove by local commercial divers (as of September 2025). Two divers can collect 2800 lbs of urchins in just one day! Sea urchins are taken to a composting facility or given to FRC for use in education programs.
Photo: Urchin collecting by Grant Downie (left), Sea urchins by Steve Lonhart, NOAA, and collected sea urchins at the docks in Bodega Bay by Dione Deaker
Growing kelp for restoration
Greater Farallones Association kelp restoration specialists grow kelp in tanks at Bodega Marine Lab in Bodega Bay, University of California, Davis, in partnership with Sonoma State University, so that spores can settle on twine for outplanting. Hundreds of baby bull kelp will grow on one roll of twine.
1. Julieta Gomez, GFA-GFNMS/CBNMS, holds up bull kelp that is being cultured in tanks at Bodega Marine Lab for kelp restoration.
2. Researchers with GFA, the sanctuary and SSU work together to cultivate spores for kelp restoration outplanting.
3. Kelp spores settle on twine in tanks, this twine is outplanted at restoration sites in Greater Farallones National Marine Sanctuary.
4. Julieta Gomez, GFA-GFNMS/CBNMS, assesses condition and abundance of sporophytes in the microscope.
5. A kelp sporophyte
Photos by Jenny Stock, NOAA
Bull kelp is an annual species that reaches maturity within one year and grows as fast as 10 inches in a single day. It typically dies off in the cooler months when it may drift offshore and eventually sink or wash ashore to beaches providing valuable nourishment to beach insect and shorebird communities.
Image credit: Gina Contolini, CASG
Outplanting kelp and monitoring
The twine with bull kelp is unravelled and placed at restoration sites to grow. Kelp cover, urchin density and the recovery of other fish and invertebrate species are being monitored and compared to control sites with no restoration efforts. The hope is that the kelp on the twine will grow into reproductive adults where they will act as a “spore bank” that will disperse to grow kelp in neighboring areas.
Twine covered in hundreds of juvenile bull kelp 1.5 months after being transplanted from the lab to Fort Ross Cove (September 2024, Left). Kelp growing off the twine in Mendocino in 2023 (right). Photos by Abbey Dias