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Intertidal Zones

Here in California we experience mixed semi-diurnal tides. Basically we have two low tides and two high tides every day. Your local paper's weather page can help you figure out the best low tides to go exploring. The rocky intertidal ecosystem is divided into different zones depending on how much of the area is exposed during low tides.

The Splash Zone is the highest and driest of the intertidal zones. Animals that can tolerate the most dry conditions live here.
The High Tide Zone is underwater only during the highest tides. Organisms that can stand up to strong waves and long exposure to air do well in this zone.
The Mid Tide Zone is covered and uncovered by the tides twice a day. Animals have adapted to the changing conditions in this zone by learning to conserve their water until the high tide covers them again.
The Low Tide Zone is usually covered by water and the creatures who make this zone home are less tolerant of being exposed to the air.
The Sub Tidal Zone is rarely exposed to the air. Some of the most exciting and delicate animals live in these area. Only on the very lowest tides of the year can you access the creatures here.

Return to the Tidepool!

Intertidal Organisms

Limpet	You can find Rough limpets in the the high and Mid Tide Zones of the tidepools. When the tide goes out the limpets cement themselves to the rocks to hold in their precious water. Limpets come in all sizes and their shells can be either rough, like these limpets, or smooth. Return to the Tidepool!
Opaleye	Many fish, like this Opaleye use the tidepools for nurseries. The tidepools offer plenty of food and places for the growing fish to hide. When they are big enough they move to deeper water bigger food and shelter. Return to the Tidepool!
Hermit Crab	Hermit crabs have no hard shell to protect the back half of their body so they borrow another shell when the snail inside is gone. In our pools the crabs prefer Black Turban Snail shells, but will make due with anything that fits! Return to the Tidepool!
Barnacles	Barnacles spend their whole loves attached to the rocks in the same place. Although they look like mollusks (clams & snails) with their hard shell, they are more closely related to crustaceans (crabs, lobster & shrimp). You can find the volcano shaped shells attached to the rocks in all the zones in the tidepools from the spray zone down to the sub-tidal zone. Return to the Tidepool!
Anemone	Anemones may look like flowers but actually belong to a group of animals called cnidarians. These animals have stinging cell on their tentacles that paralyze prey that swims too close. You might find aggregate anemones (large clusters of small animals) or Giant Green Anemones that can be 6" diameter in the tidepools. Return to the Tidepool!
Octopus	Sometimes if you are lucky you may spot one of the most elusive tidepool creatures. Octopus are mollusks and related animals like snails and mussels. Octopus are shy and great at camouflage. They can change color to match their surroundings and to match their moods. Return to the Tidepool!
Shore Crab	Look for shore crabs scurrying into cracks and crevices in the tidepools. Striped Shore Crabs are most common in our tidepools and are a range of sizes from as small as a penny to as big as a dollar bill. Shore crabs scavenge through the tidepools looking for their next meal. Unlike hermit crabs, shore crabs can give you a good pinch with their claws. Return to the Tidepool!
Turban Snail	Black Turban snails are very common in the tidepools. They graze on algae in the tidepools just like snails in your garden graze on plants. When the snail inside the shell dies, hermit crabs often move in to make it their home. Return to the Tidepool!
Gooseneck Barnacles	They don't look like other kinds of barnacles, but they are still related. Look for Gooseneck Barnacles tucked in the rocks between mussels and Acorn Barnacles. Underwater Gooseneck Barnacles extend feathery gills to trap their lunch and dinner. Return to the Tidepool!
Mussels	Mussles spend their entire lives attached to rocks by "bissal thread." Mussles are part of a group of mollusks called bi-valves. Bi-valves have two shells that have a hinged joint like clams and scallops. Both the California Mussel and the Blue Mussel live in our tidepools. Return to the Tidepool!
Sea Star	Many people still call these star fish, but they aren't related to fish at all. Sea stars are echinoderms and its relatives include sea urchins and sand dollars. You might find Ochre Stars or Bat Stars in the Orange County tidepools. These stars usually have five rays, or arms, and range in color from orange to red to purple. Return to the Tidepool!
Chiton	Chitons look like animals from a prehistoric era. In fact they haven't changed much from when they first appeared. Chitons are cousins to clams and snails even thought they look like rollie-pollies you might find in your garden. They have a single foot they use to move through the tidepools and scrape their algae dinner off the rocks. Return to the Tidepool!
Algae	Algae is the bottom of the food chain for the animals in the intertidal zone. It can be very large, like Bull Kelp or Giant Kelp, or small like the coralline algae that we find in the tidepools. Not only does algae provide food for many creatures, but it also offers protection and shelter from predators and the elements . Return to the Tidepool!