Estuarine Subtidal Rock and Boulders: Open, Deep

These habitats are found in narrow channels or headlands where currents are rapid and remove sediment. Because freshwater flowing in can remain layered in shallower water, conditions in these habitats are essentially marine.

Common Species

Ascidians, especially Ascidia paratropa, Chelyosoma productum, Corella willmeriana, Boltenia villosa; the large barnacle Balanus nubilus, the hydrocoral Allopora sp., the anemone Metridium sp. and the colonial zoanthid Epizoanthus scotinus, the white urchin Strongylocentrotus pallidus, the brachiopods Terebratalia and Terebratulina, the sea cucumbers Eupentacta spp., and the tubiculous polychaete Serpula vermicularis.

Below 20 m, especially in the Strait of Georgia, other species appear: glass sponges (Rhabdocalyptus dawsoni, Aphrocallistes vastus), brachiopods such as Terebratulina unguicula, the cup coral Balanophyllia elegans, the sessile sea cucumber Psolus chitonoides.

Sites Surveyed

Lower Puget Sound, Boundary Pass, Howe Sound, British Columbia.


McDaniel, 1973; Wennekens, 1959; R. Anderson unpubl. data.