Tide Pools
Rock Beaches

Rock beaches with high or moderate exposure occur along the Strait of Juan de Fuca; on portions of the west side of Whidbey Island; the southwest shore of San Juan Island, and the southern end of Lopez Island. Protected rock beaches are most common in northern Puget Sound. Rock beaches are rare in central and southern Puget Sound, occurring only in a few places.

Rock beaches are made of bedrock and boulders too big to be moved by currents or waves. Rocks provide homes for marine life in cracks, crevices, and tidepools.

Anchors For Anything

Most life on rocky shores anchor themselves with suction, glues, tendrils, and threads. Seaweeds use "holdfasts" to grab onto rocky surfaces. Some creatures on rocky shores do not attach themselves; worms, for example, find a home in mussel beds and hermit crabs live in tidepools.

Rock Beach: Habitat Zones

river otter on rock beach
  • Further Up The Beach
    Harbor seals and river otters haul out on rock beaches. Raccoons, mink, and skunks also forage here. At low tide, garter snakes may feed. Shorebirds, gulls, bald eagles, and peregrine falcons also hunt for meals here.
  • Splash Zone
    A few tough species can survive the drying and exposure here; Lichens often form a distinct band. The rock slater, an isopod which feeds on decaying algae, can be found in this zone.
    Pacific Oyster
  • Mid Intertidal Zone
    In Hood canal, the Pacific oyster dominates this zone. Rockweed, sea lettuce, sea cabbage, and honey ware kelp also survive here.
  • Lower Intertidal Zone
    This area offers a more stable home for a wider variety of life including; starfish, sea cucumbers, anemones, sea urchins, purple sea stars, and crabs. Sea cucumbers hide among boulders and crevices. Three species of urchins live here.
  • Shallow Water, Subtidal
    Because this area is never uncovered by tides, it is the least stressful for marine life. Large kelps are found here. Juvenile salmon feed on small invertebrates on their way to the sea. Herring attach their eggs to subtidal vegetation.
    Tough Rocks, Delicate Ecosystem

    Rock beaches are exciting places for exploring marine life. However, visitors can harm the wildlife. When people collect species for souvenirs, they deplete populations and upset the ecological balance of the shore. It can take years for a picked-over beach to re­establish a healthy community.

    • Take only pictures and memories. Leave marine life for others to enjoy.

    Related Links

    Beaches, US EPA. Find information on beach basics, beach health, and technical resources. 

    The Beach and Your Coastal Watershed, US EPA Fact Sheet (1998). Beaches and their function within a coastal watershed. Impacts on beaches and EPA's programs to protect beaches.  

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