Marine Subtidal Rock and Boulders: Moderate to High Energy, Deep

Rocky areas deeper than 15 meters with fairly high currents are common in the San Juan Islands and probably in the Strait of Juan de Fuca.  These have few kelps relative to shallower areas.  Encrusting invertebrates dominate the space.

Diagnostic Species

The giant white anemone Metridium sp.

Common Associates

Encrusting and erect coralline algae, foliose red algae such as Callophyllis spp., red and green urchins, brachiopods (several species), the polychaetes Sabellaria cementarium and Dodecaceria sp., the cucumbers Eupentacta quinquesemita and Psolus chitonoides, the cup coral Balanophyllia elegans and the soft coral Gersemia sp., the anemones Urticina spp. and Cribrinopsis fernaldi, the scallops Chlamys spp. and Hinnites giganteus, the large barnacle Balanus nubilus, and the seastar Orthasterias koehleri.  Even deeper areas (below 25 m) have no erect algae and are dominated by brachiopods (Terebratalia transversa and Terebratulina unguicula), the large anemone Metridium senile, bryozoans and hydroids, encrusting cnidarians such as Epizoanthus scotinus and Allopora spp., and the “white” urchin Strongylocentrotus pallidus.  The basket star Gorgonocephalus eucnemis is common in patches.  Fishes include rockfish, lingcod, gobies, and sculpins in the genus Artedius.

Sites Surveyed

Numerous sites in the San Juan Islands (few complete surveys).


Vadas, 1968; Shelford, 1935; Neushul, 1965 and 1967; Moulton, 1977; R. Shimek, R. Anderson, and C. Staude unpubl. data.