Kelp Forest Restoration Project

An urchin barren before restoration (top) and healthy kelp regrowing after restoration (bottom).

Urchins Living in Barrens

These urchins are malnourished and miniature, often diseased, and of no value to the ecosystem nor fishermen. In contrast, urchins found living in kelp forests are healthier and have larger gonads (Uni), the edible part of the sea urchin common in sushi.

Manually culling purple urchins jump-starts the return of a healthy kelp forest and leaves healthy urchins on the reef. All our partners, including the sea urchin fishermen, understand this cycle, and are helping to bring the kelp back as quickly as possible.

urchins 5-12-11-16

Approximately 150 acres of urchin barrens were identified along the rocky reefs off Palos Verdes.

With funding provided by the Montrose Settlements Restoration Program, restoration began in 2013 to reduce the urchin population density and allow the recovery of giant kelp.

Today, the kelp forest community off Palos Verdes is responding positively to our restoration efforts. What once was sea urchin and rock has transformed into budding kelp forests increasing the abundance of life and diversity on the reefs. The reestablishment of kelp forests will aid local fisheries, enhance recreational opportunities, and help protect our coast.

Learn More

Documents and Reports

Urchin Paper

Project Report – July 2017 to June 2018

Project Partners

Commercial Sea Urchin Harvesters

Montrose Settlement Restoration Program

Vantuna Research Group

Tom Boyd Images

Why Restore Kelp Forests?

Kelp forests are the rainforests of the sea.

The submarine forests off the southern California coast are known to be some of the most diverse and productive ecosystems in the world. They provide habitat and food for over 700 species of algae, invertebrates, and fish. Many of these kelp forests support large sport and commercial fisheries, as well as a vibrant recreational diving industry.

Over the past 100 years, the Palos Verdes Peninsula has lost approximately 75% of its giant kelp canopy. Sedimentation, development, urban runoff and storms slowed kelp growth. At the same time, overfishing these kelp forest reefs contributed to the loss of key urchin predators and competitors. This allowed purple urchins, a dominant kelp herbivore, to overrun the reef and devour the remaining kelp.

If left alone, kelp forest recovery may take decades.

To speed recovery of this vital ecosystem a partnership of researchers, fishermen and conservationists – led by The Bay Foundation (TBF) – started removing the overly abundant purple sea urchins, changing a desolate monoculture into a diverse and resilient ecosystem.

Progress to Date:

46 acres of restored kelp forest in 2 coves and 4 open shore reefs off the PV peninsula.

5 commercial urchin fishermen working on project.

Over 7500 hours underwater restoring kelp.

Purple urchin density reduced from an average of 30 to ~2 per square meter.

Red urchins increase in gonad (uni) weight by 168% solely at restoration sites off Palos Verdes.

Increases in kelp, invertebrate, and overall fish diversity and biomass.

Recreationally targeted finfish increase in density and biomass.

Seasonal Scientific Field Technician Opportunities

This effort will restore over 150 acres of kelp forest. The Bay Foundation offers paid seasonal AAUS dive technician positions annually. These positions will provide hands-on field experience working directly with experts in the field of marine ecology.

“I can only compare these great aquatic forests…with the terrestrial ones in the intertropical regions. Yet if in any country a forest was destroyed, I do not believe nearly so many species of animals would perish as would here from the destruction of the kelp.”

– Charles Darwin, 1 June 1834 Tierra Del Fuego, Chile


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