Kelp Restoration

TODD GROSS   Oct 04, 2026

Purple Sea Urchin Removal & Kelp Restoration on the California Coast

 

Protecting California's Kelp Forests Through Conservation Diving

California's kelp forests are among the most important marine ecosystems on the Pacific Coast. These underwater forests provide habitat, food and shelter for an incredible variety of marine life while supporting recreational diving, fishing and coastal communities.

Today, many areas of the Northern California coast are struggling with severe kelp loss.

One important factor is the dramatic increase in purple sea urchin populations in areas where the ecological balance has been disrupted. Although the purple sea urchin is a native California species and is not technically an invasive species, unnaturally high densities can create intense grazing pressure that prevents kelp from recovering.

This is why purple sea urchin removal, targeted culling and kelp restoration have become important conservation tools along the California coast.

Purple Sea Urchins and the Kelp Forest Crisis

Purple sea urchins (Strongylocentrotus purpuratus) are naturally occurring members of California's marine ecosystem. In a healthy kelp forest, they play an important ecological role by consuming algae and kelp.

The problem occurs when the balance between kelp, urchins and their predators is disrupted.

When large numbers of purple urchins accumulate in an area where kelp has already disappeared, they can continue grazing on new kelp growth. This can create an urchin barren—an underwater landscape dominated by urchins and bare rock instead of a thriving kelp forest.

Northern California has experienced dramatic kelp declines, particularly following major ecological disturbances and changes in ocean conditions.

Reducing excessive urchin densities in carefully selected areas can help lower grazing pressure and create an opportunity for kelp to return.

What Is Purple Sea Urchin Culling?

Purple sea urchin culling is the targeted reduction of excessive urchin populations within a designated restoration area.

Depending on the specific conservation program and applicable regulations, trained divers may manually remove purple sea urchins or use approved hand tools to cull them underwater.

The objective is not to eliminate purple sea urchins from California.

Instead, the goal is to reduce excessive grazing pressure and restore ecological balance within targeted kelp-restoration areas.

Successful restoration requires careful planning, trained divers, environmental awareness and ongoing monitoring.

The Caspar Cove Kelp Restoration Project

The Caspar Cove Project on California's Mendocino coast is an important example of community-based kelp restoration.

Through the Watermen's Alliance and participating conservation partners, recreational divers have helped remove large numbers of purple sea urchins from designated areas in an effort to reduce grazing pressure and provide conditions that may allow bull kelp to recover.

The project demonstrates the potential of combining:

• Recreational scuba divers

• Conservation organizations

• Scientists and researchers

• Local communities

• Commercial and recreational ocean users

• Diving equipment and logistical support

Caspar Cove also demonstrates why conservation diving requires an ongoing commitment. Removing urchins is not a one-time solution. Restoration areas must be monitored and maintained while scientists evaluate kelp recovery and changing environmental conditions.

P.U.R.P. — Purple Urchin Removal Project

The Purple Urchin Removal Project (P.U.R.P.) represents another example of divers taking an active role in California kelp restoration.

P.U.R.P. brings members of the diving community together to participate in targeted purple sea urchin removal efforts, including restoration work along the Sonoma Coast.

Projects such as P.U.R.P. demonstrate how recreational divers can become active participants in marine conservation rather than simply observers of the underwater environment.

For divers who spend time beneath California's coastal waters, the difference between a healthy kelp forest and an urchin barren is impossible to ignore.

Conservation Diving: Turning Divers Into Stewards

Scuba divers have a unique relationship with the ocean.

We don't just see the ocean from the shoreline—we enter it.

We swim through kelp forests, observe marine life and experience firsthand the changes taking place beneath the surface.

That experience gives divers an opportunity to become ocean stewards.

Participating in properly organized purple sea urchin removal projects allows trained divers to contribute their time, skills and physical effort to important conservation work.

Conservation diving can include:

• Purple sea urchin removal

• Kelp restoration projects

• Underwater habitat monitoring

• Marine-life surveys

• Scientific data collection

• Environmental education

• Restoration support and logistics

Pinnacles Dive Center Supports Kelp Restoration

At Pinnacles Dive Center, we believe that the diving community has a responsibility to protect the underwater environments we enjoy.

We fully support responsible, science-based efforts to restore California's kelp forests and reduce excessive purple sea urchin populations in designated restoration areas.

Pinnacles Dive Center is proud to support local conservation programs by providing diving equipment, gear and logistical support that help conservation divers continue their work.

Conservation projects require reliable equipment and dedicated divers. Tanks, regulators, BCDs, exposure protection, weights and other essential scuba equipment allow volunteers to spend more time in the water contributing to restoration efforts.

Supporting conservation means supporting the people doing the work.

That's why Pinnacles Dive Center is committed to helping local conservation programs and participating divers have access to the equipment and support they need to continue their efforts.

Why Kelp Restoration Matters

Kelp forests provide critical habitat for California's marine ecosystem.

A healthy kelp forest can support fish, invertebrates, marine mammals and countless other organisms. Kelp also contributes to the complex food web that makes California's coastal waters so biologically productive.

Restoring kelp is therefore about much more than bringing back a single plant.

It is about restoring an ecosystem.

Purple sea urchin removal is one potential tool in that restoration process, but it is not a stand-alone solution. Successful kelp recovery depends on many factors, including ocean temperatures, nutrient availability, predator populations, marine disease, storms and other environmental conditions.

That is why responsible restoration programs combine urchin removal with scientific monitoring and long-term ecosystem management.

Divers Can Be Part of the Solution

The future of California's kelp forests will depend on collaboration.

Scientists provide research and monitoring. Conservation organizations coordinate restoration. Communities provide volunteers. And divers provide something especially valuable—the ability and willingness to work underwater.

Organizations such as the Watermen's Alliance, Caspar Cove Project and P.U.R.P. demonstrate what can happen when people who care about the ocean come together to restore it.

At Pinnacles Dive Center, we believe every diver has the opportunity to become a better steward of the underwater environment.

Dive for Conservation. Dive for Kelp. Dive for the Future.

The California coast has given generations of divers incredible experiences beneath the surface.

Now it is our turn to give something back.

Pinnacles Dive Center proudly supports responsible purple sea urchin removal, kelp restoration and conservation diving efforts throughout Northern California.

Together, we can help give California's kelp forests an opportunity to recover.

Prepared Divers. Safer Divers. Conservation-Minded Divers.