In the Piedras Blancas SMR the algae was dominated by the bull kelp (N. leutkeana) with high densities of the sub-canopy kelp Laminaria and Pterygophora. The underwater environment is primarily slight relief bedrock with elements of moderate relief boulders and cobble. Predatory sun stars (P. helianthoides) were abundant at the MPA sites as were the giant sea star (P. giganteus). High numbers of blue rockfish (S. mystinus) are consistently found here.
The reference sites for Piedras blancas SMR are similar to the MPA sites with slight relief bedrock as the dominant benthic habitat of the sites. The major canopy forming algae in these sites is the giant kelp Macrocystis and the understory is dominated by Pterygophora. The benthic habitat is populated by the bat star (A. miniata) particularly but also exist predators such as the giant sea star (P. giganteus) and the sun star (P. helianthoides). Rockfish are in abundance here such as the blue rock fish (S. mystinus) but the demersal species kelp greenling (H. decagrammus) and lingcod (Ophiodon elongatus) were also seen here in relative abundance.