University of California institute of Marine Science - S. Central La Jolla

Restoration Project

University of California institute of Marine Science - S. Central La Jolla

Restoration Objective:

Restoration was undertaken to restore a historical kelp bed.

Site Selection Criteria:

The selected site had experienced 95% loss of historical kelp bed extent.

Cause Of Decline:

During the warm water years from 1957 to 1959, about 95 percent of the La Jolla kelp bed disappeared. Most of the inshore area was populated with short-statured seaweeds, hindering the spread of Macrocystis. Offshore, starting at depths of 40 to 50 feet, large concentrations of urchins prevented development of any vegetation whatsoever.

Key Reasons For Decline:


Scientific Paper

Kelp Habitat Improvement Project. Annual Report 1

W.J. North

Site Observations:

Observation Date

1st Jun 1966 – 1st Jun 1968

Action Summary:

From 1966, two methods were used for controlling urchins. Quicklime was employed only when animals sensitive to the chemical were absent. When such animals were present, hammers were used to crush urchins. Urchins were primarily eliminated at the borders of existing kelp patches.

Lessons Learned:

Aerial cover was used to assess kelp regeneration.

Project Outcomes:

Kelp all but disappeared at the extreme northern portion of the bed due to temperature damage. Substantial canopy deterioration occurred during winter 1967-68 in certain inshore areas, but causes were not identified. Many small plants were noted which will likely develop into healthy kelp stands. The bed was harvested in February 1968 for the first time in five years.

Nature of Disturbance:

Red tides, grazing by fishes and warm water influxes inhibited restoration efforts.

Key Reasons For Decline:


Area of Restoration (Ha)


Indicator Data:


Ending Value:

Starting Value: