Naturalist Guide: Intertidal Zone

The rocky shoreline stretching from the Arena Cove north to the Lighthouse is ideal habitat for intertidal creatures. The intertidal zone is the narrow edge of the ocean that lies between high and low tide. Although many animals visit, only those specially adapted to its challenging conditions can live there full time. Temperature, salinity, and moisture levels all change as the tides come and go. For intertidal animals, it is not enough to be able to breathe underwater while being dashed about by rough waves; they must also survive exposure to open air and the drying, warming effects of the sun. Sea stars and fish, like the tidepool sculpin, can’t get completely dried out in the sun, so they find tidepools to stay in during low tide. Snails, barnacles, and mussels avoid drying out by holding seawater inside their shells and by hiding under seaweed. These techniques also protect them from shorebirds, like the black oystercatcher, that rely on the intertidal zone for food.

sea anemones in the intertidal zone
Sea anemones in the intertidal zone.
Black oystercatcher looking for food
Black oystercatcher looking for food.

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