Tide Pools
Gravel beach. Photo by Wolf Bauer.
Gravel Beaches

Gravel beaches are by far the most common beaches in Puget Sound. A gravel beach can be made of small boulders or mud, sand, and gravel mixed together.


Hide and Seek

Mixed gravel beaches often harbor more marine creatures. This is because they find hiding places from predators, particularly at low tide. Several species of crabs, such as purple shore crabs, porcelain crabs, and hairy cancer crabs frequently hide under cobble sized rocks. Hundreds of isopods and amphipods can often be found hiding under rocks.

Some species of fish also seek protection under rocks while the tide is low. These fish include: northern clingfish, penpoint gunnels, high cockscomb, and sometimes sculpins.

Gravel Beach: Habitat Zones

  • Higher Up The Beach
    A gravel beach with a high percentage of mud and sand will have more vegetation than a coarser gravel beach.
  • Mid Intertidal Zone
    Pockets of sand hold burrowing worms and butter clams, native littleneck clams, Manila clams, and soft-shell clams. In Hood Canal and central and southern Puget Sound, bay mussels occur in large patches, especially in the alluvial fans formed by small creeks flowing to the beach.
  • Lower Intertidal Zone
    On finer composition beaches, the amount of vegetation may increase. Eelgrass often grows, along with the plants and animals associated with it. Sea lettuce can also be found here. Large brown algae such as seersucker, sea collander, and sugar wrack may occur in lower portions of the shore.
  • Shallow Water, Subtidal
    Harbor seals will feed close to shore along mixed gravel beaches and have been observed mating in the shallow waters in the more isolated areas.
    Gravel Beaches: Help the Habitat

    • One of the biggest threats to gravel beach habitats comes from clam digging. Open holes created by shellfish harvesters can expose marine animals to predators. Large piles left by diggers can also suffocate shellfish and other intertidal creatures. Filling in holes helps clams survive, as well as many fish, birds, and crabs nearby.
    • Before harvesting shellfish, contact your local county health department for safety information. Be sure to get a shellfish license from the Department of Fish and Wildlife. Information on beach closures is available at the Department of Health's Beach Closure web page.

    Related Links

    Recreational Shellfish Safety Information, Washington State Department of Health. Before you dig for shellfish, visit this web page.

    Shellfish Rules and Regulations, Washington Department of Fish & Wildlife. Regulations and general information on shellfish harvesting.

    Clam Diggers: Why Fill in Your Holes? Washington Department of Fish & Wildlife.  

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