Restoration Project

University of California institute of Marine Science - Mission Bay

Restoration Objective:

The objective of this study was to determine the effectiveness of liming on urchin control, and to test possible harmful side effects to other species.

Site Selection Criteria:

Sites were selected that had previous kelp cover, close proximity to remnant kelp beds and high urchin densities.

Cause Of Decline:

High sea surface temperatures have contributed to a decline in historical populations of Macrocystis pyrifera.

Key Reasons For Decline:

Ocean warming

Scientific Paper

Kelp Habitat Improvement Project Final Report 1 Dec., 1963

W. North, .


University of California Institute of Marine Science

Site Observations:

Observation Date

3rd May 1962 – 15th Sep 1963

Action Summary:

Quicklime powder was distributed by divers from cans onto concentrated swarms of urchins. Rocks heavily populated with S. purpuratus and S. franciscanus were limed on three occasions in the summer and spring of 1962. Liming was carried our near stands of Macrocystis and Egregia, and at concentrations of 0.2 and 0.4 pounds per square foot. In May 1962, CaO powder, CaO pebbles and Ca(OH)2 powder were applied to small areas.

Lessons Learned:

Most Macrocystis juveniles survived liming, 5 out of 22 died.

Project Outcomes:

In areas with 5 and 17 Macrocystis juveniles, 5 and 12 survived liming and were growing rapidly to adulthood in June.

Key Reasons For Decline:

Ocean warming

Area of Restoration (In Square Metres)


Indicator Data:


Ending Value:

Starting Value:

Juvenile Kelp Density

/ m2
/ m2
Cost Currency:USD