Bay Foundation - Hawthorne

Restoration Project

Bay Foundation - Hawthorne

Restoration Objective:

This project aimed to restore kelp forests to rocky reefs to improve the biomass and productivity associated with rocky reefs. It also aimed to engage the local community in management of the kelp forest ecosystem.

Site Selection Criteria:

Sites were selected that historically had populations of kelp.

Cause Of Decline:

California kelp forests have been severely depleted by human activity, mainly overfishing, which has caused several ecological shifts within the habitat, primarily attributed to the loss of key predator species, including otters and predatory fish. This has resulted in an increased abundance of sea urchins, contributing to kelp overgrazing.

Key Reasons For Decline:


Scientific Paper

Palo Verdes kelp forest restoration project, year 5: July 2017–June 2018. The Bay Foundation

P. House, A. Barilotti, H. Burdick, T. Ford, J. Williams, C. Williams, D. Pondella
Los Angeles CA.


Site Observations:

Observation Date

11th Jun 2013 – 11th Jul 2017

Action Summary:

Citizen scientists culled urchins, reducing sea urchin density from as high as 100 sea urchins per square meter to < 2 sea urchins per square meter.

Lessons Learned:

This project shows the success of using community engagement and in particular collaboration with commercial urchin fishers to curb urchin density for kelp restoration. Urchins were removed periodically when densities were seen to increase above 2 urchins per square metre.

Project Outcomes:

In Hawthorne, an area slightly less than an acre outside of the previous restored area was found supporting high densities of purple sea urchins and was cleared during this year of the project. In year 5 of the project, a deeper section adjacent to the previously restored area was identified with high urchin densities and was restored.

Key Reasons For Decline:


Area of Restoration (Ha)


Indicator Data:


Ending Value:

Starting Value:

Adult Kelp Count