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.
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.
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.