Olympic Coast National Marine Sanctuary Living Sanctuary section includes Marine Life, Habitats, Ocean Environment, History and Culture
Olympic Coast National Marine Sanctuary Living Sanctuary section includes Marine Life, Habitats, Ocean Environment, History and Culture
Olympic Coast National Marine Sanctuary Living Sanctuary section includes Marine Life, Habitats, Ocean Environment, History and Culture

Rocky Reefs

photo of a china rockfish Much of Olympic Coast National Marine Sanctuary's underwater landscape mirrors its coastline. Where the lowland is gentle, the beaches and underwater environment are also gentle - the seafloor a mix of broad gravel, sand and silt flats. But the coastline found in the northern part of the sanctuary – rocky cliffs, broad terraces of bedrock exposed at low tide, seastacks, islets and barely-submerged wash rocks – reflects what lies underwater. Where the shore ends abruptly in jumbled rocks, the same landforms extend seaward, beneath the waves and out of sight.

photo of seastars on rock Rocky reef habitats in the sanctuary teem with life. In the ocean, "structure" is the key to habitat. A jumbled underwater landscape provides such structure. Crevices and caves offer shelter. Channels and passageways are "highways" connecting different parts of the convoluted underwater reef realm and allowing fish roam with relative protection. Animal life clings to every surface, creating food and complex micro-environments for invertebrates and fishes. In the upper layers of water where sunlight penetrates, seaweeds thrive. Deeper, in the darkness of the sea floor, rocky environments support corals, sponges and a host of other organisms. Rockfish claim territories where the subtle topography creates currents and eddies that concentrate drifting food and give them shelter in the current so they can conserve energy.

photo of an octopus Many rocky reefs on the Olympic Coast represent islands on the seafloor and are surrounded by broad expanses of sandy seafloor. Among these "islands" fish like lingcod, sculpins, greenling and rockfish breed, rear their young and feed, often staying in the same vicinity for life. The Pacific giant octopus, sea urchins, predatory sea stars and other invertebrates thrive in these food-rich, oxygen-rich and diverse habitats.



Contact for page content: Robert Steelquist
Photo of peach coral
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