"Coastal view, Cabrillo National Monument, 2015." by U.S. National Park Service , public domain
![]() | Site BulletinsLife in the Intertidal Zone |
Brochure about Life in the Intertidal Zone at Cabrillo National Monument (NM) in California. Published by the National Park Service (NPS).
featured in
![]() | National Parks Pocket Maps | ![]() |
![]() | California Pocket Maps | ![]() |
covered parks
Cabrillo
National Park Service
U.S. Department of the Interior
Cabrillo National Monument
Life in the Rocky Intertidal Zone
Tidepools provide a home for many animals. Tidepools are created by the
changing water level, or tides. The high energy waves make this a harsh habitat,
but the animals living here have adapted over time. When the earth, sun and
moon align during the full and new moon we have extreme high and low tides.
Generally, there are two high tides and two low tides a day. An example of low
and high tide is seen on the right.
There are three zones within the tidepools: the high zone, the middle zone, and
the low zone. Animals are distributed based on their adaptations to different
living (competition and predation) and no living (wave action and water loss)
factors. The tidepools at Cabrillo are protected and have been monitored by the
National Park Service since 1990. You may notice bolts in the rocky intertidal,
these are used to assist scientists in gathering data to monitor changes.
Low Tide
Tidepool Etiquette:
Human impact can hurt the animals. As you explore the tidepools, you may
touch the animals living here, but only as gently as you would touch your own
eyeball. Some animals may die if moved even a few inches from where they are
found. Federal law prohibits collection and removal of any shells, rocks and
marine specimens. Also, be aware of the changing tides, slippery rocks and
unstable cliffs. Have fun exploring!
The high zone is covered by the highest tides. Often this area is only sprayed by the crashing
waves. The animals who live here must endure a long time without water. Below are common
examples of what you can find in the high zone.
High Zone
(Supralittoral or
Spray Zone)
Mussels and
Barnacles
High Tide
Thatched Barnacles
Periwinkles
Gooseneck Barnacles
Acorn Barnacles
Owl Limpet
Conspicuous Chiton
Limpets
Shore Crab
Chiton
*Photos are not to scale. Thank you to the Tams
for most of these photos.
The best time to visit the tidepools is during the
new or full moon; a negative low tide is
recommended for the best exploring.
Isopod
Hermit Crab
If you are interested in learning more, visit the
tidepool education table or volunteer to help
protect this unique and beautiful place.
For volunteer opportunities contact:
Cabr_volunteers@nps.gov
Middle Zone
(Littoral Zone)
The middle zone is covered by the highest tides and exposed by the lowest tides. The
animals here have to be able to live both in and out of water. The anemones close up and
cover themselves in bits of shell and other debris in order to retain moisture during low
tide. Below are some examples of species in the middle zone.
Solitary Anemone
Brooding Anemones
Closed
Sea/Surf Grass
Sea Bubble
Low Zone
(Sublittoral or
Subtidal Zone)
Scaly Tube Snail
Aggregate Anemones
Closed
Open
Black Tegula Snail
Sea lettuce
Kellet’s Whelk
Feather Boa Kelp
Coralline Red Algae
Sponge Weed/
Dead Mans’ Fingers
Sandcastle Worms
Sargasso Weed
Keyhole Limpet
The low zone is only uncovered during the lowest tides. Animals here are submerged in
water most of the time. Some of the animals in this zone like to hide under surfgrass
because it provides shelter. Below are some animals found in the low zone.
Knobby Sea Star
Brittle Star
Sea Urchin
Bat Star
Opalescent
Nudibranch
Brown-Ringed
Nudibranch
Rosy Nudibranch
Yellow Umbrella Slug
Opaleye
Open
Wooly Sculpin
Garibaldi
California Moray Eel
California Sea Hare
Chestnut Cowry
This brochure was made possible through the work of Katie Eskridge, a Girl Scout who used the tidepools as the subject for her Gold Award Project .
EXPERIENCE YOUR AMERICA
™
Kelp Crab
Octopus