National Oceanic and Atmospheric Administration - San Luis

Restoration Project

National Oceanic and Atmospheric Administration - San Luis

Restoration Objective:

This artificial reef was installed to determine whether an artificial reef could be designed to encourage algal development that provides habitat for blue, olive, and yellowtail young-of-the year (YOY) rockfish species. It also assessed whether YOY recruitment at the artificial reef site was higher than at the natural reef habitat, and determined if annual fish recruitment would continue over time.

Site Selection Criteria:

The site selected consisted of a sandy seafloor area that was near enough to natural reefs to enhance fish recruitment, but large enough to allow for construction and expansion of the artificial reef without encroaching on nearby natural reefs. An average depth of 17m was chosen so that the tops of the artificial reefs would be at similar depths as the local natural reefs.

Key Reasons For Decline:

Ocean warming

Scientific Paper

Comparison of rockfish recruitment of nearshore artificial and natural reefs off the coast of central California

E.M. Danner, T.C. Wilson, R.E. Schlotterbeck
Bulletin of Marine Science, Vol. 55.

Site Observations:

Observation Date

6th Jun 1985 – 15th Jul 1990

Action Summary:

Concrete, rubble and broken tribar stone from a damaged breakwater were towed out to sea and released from a barge to create four artificial reef modules. 27,000 tons of materials were dropped into four nearly equal sized modules, separated by distances of 15 to 100 m, with their axes aligned similarly to local natural reefs.

Lessons Learned:

Higher fish abundance was initially observed at the artificial reefs, but this declined to become similar to the natural sites, possibly due to the shift from Nereocystis to Pterygophora dominated seaweed communities.

Project Outcomes:

Seaweeds recruited rapidly at the artificial reef site, with dense beds of Pterygophora and Nereocystis developing within 2 years after construction. Within the first 3 years, cover of foliose red algae at all modules was similar to that found at natural sites. The density of Nereocystis declined rapidly however, as the densities of the perennial overstory kelp Pterygophora increased and became the dominant overstory kelp. It appears that the algal community at the artificial reef modules has undergone natural succession to become similar in algal species composition to the local natural reef sites.

Key Reasons For Decline:

Ocean warming

Area of Restoration (Ha)


Indicator Data:


Ending Value:

Starting Value:

Adult Kelp Density

/ m2
/ m2