TIDEPOOL CREATURES
Common tidepool creatures that inhabit the Pacific's rocky coastline.
Black Tegula
Tegula funebralis
Size: up to 1 inch
Diet: Micro algae.
Description: The Black Tegula is a small common snail found on the rocky intertidal zone found well above the low zone. The Black Tegula has a very hard shell, can live for 100+ years, and scrapes algae using its specialized tongue, the radula. A similar species, the Brown Tegula, occupies the same intertidal zone. It has a light chestnut shell. Hermit Crabs of the genus Pagurus can be seen using the shells of this snail.
Range: Oregon to California. Uncommon in Southern California.
Eroded Periwinkle
Littorina keenae
Size: 3/4 inch
Diet: micro algae and seaweed.
Description: The Eroded Periwinkle is a type of snail commonly found on the rocky shores of California. It lives on the high intertidal zone, for it's shell is commonly eroded by the waves. The winkles at the Aquarium eat algae using a radula.
Range: Oregon to Baja, Mexico.
Lottia Limpets
Lottia spp.
Size: 3/4 inch - 4 inch
Diet: Micro algae
Description: The genus Lottia is a small group of limpets with a conical shaped shell, two triangular eyestalks. The shel varies from the size of your nail, to 2" across. The Fingernail limpet and Rough limpet live in the splash zone, because their shells can withstand the waves. Bigger species like the Plate Limpet or the Giant Owl Limpet live a little more than four years in the wild, and ten years in the CCAG. They live in the lower intertidal zone.
Range: Alaska to Baja
Dogwinkle
Nucella spp.
Size: 1 inch -3 inch
Diet: Mussels, shellfish
The genus Nucella is a family of predatory snails resembling Whelks. Dogwinkles are found on the Atlantic and the Pacific. They are normally found in mussel beds, drilling shells of mussels. The genus is capable of drilling into shells by secreting an acid and drilling in using a specialized tongue called the radula.
Range: Alaska to Central California
Striped Shore Crab
Pachygrapsus crassipes
Size: 1-1.75 inches
Diet: Algae, Carrion, Snails, and other crabs
Description: Black carapace mottled black, purple or green. Pincers equal with boxy carapace. Males larger than Females. Legs somewhat flattened. Found eating algae out of water during low tide, in rock creases, and under rocks. Can be seen feeding on algae with spoon tipped pincers at low tide
Habitat: Rock shores. mussel beds and estuaries. High to low intertidal. A similar species, Pacific Mottled Shore Crab (P. socius) is found from Baja California to Central America. This crab has burgundy pincers that fade abruptly to white. The crab also contains more leg hairs, which makes it easy to differentiate from P. crassipes.
Range: BC to Baja, Mexico
Purple Shore Crab
Hemigrapsus nudus
Size: 1-2 inches
Diet: Algae, Carrion, Snails, Seaweed
Description: Purple carapace, sometimes olive green, olive brown, white and red, but other color variations usually occur in juveniles. Pincers equal with purple spotted patterns. Males larger than Females. Legs tipped with yellow. Usually found under rocks. Feeds at night.
Habitat: Tidepools and sometimes rock crevices. High to low intertidal.
Range: Alaska to Southern California
Yellow Shore Crab
Hemigrapsus oregonensis
Size: 1-1.75 inches
Diet: Algae, Carrion, Snails, and other crabs
Description: Yellow, green or white carapace, lighter speckles present. Pincers equal with curved carapace. Males larger than Females. Legs somewhat flattened, hairy.
Habitat: Bays and estuaries. Mid intertidal.
Range: Oregon to Baja, Mexico.
California Mussel
Mytilus californianus
Size: 4-10 inches
Diet: Small zooplankton
Description: Blue-black shell. Occurs in large densities along CA coast. Is also found with Goose Barnacles. Predatory snails, including the dogwinkle, drill into the shell to eat the flesh. It is also eaten by humans, birds, marine mammals, dogwinkles and other predatory snails and crabs.
Habitat: Rock cliffs and tidepools
Range: Northern Alaska to Baja, Mexico
Aggregating Anemone
Anthopleura elegantissima
Size: 3-10 inches diameter
Diet: Carrion, barnacle molts, crabs.
Description: Bright pink tentacles fading into light pink/green. Disk contains green or yellow stripes radiating from mouth. Found retracted out of water during low tide, in rock creases, and in large numbers covering rocks. These animals can clone by splitting into two. 2 colonies may sting each other for dominance over territory. A cousin, the Giant Green Anemone (Anthopleura xanthogrammica) is solitary, emerald green and wider than this species. The two populations often overlap.
Habitat: Rock shores. mussel beds and estuaries; high to low intertidal zone.
Range: Oregon to Southern California
Acorn Barnacle
spp. Balanomorpha
Size: 0.5" across at max.
Diet: Algae.
Description: conical, white, usually atatched to rocks and mussels. Found in large numbers in bays and estuaries. When the colony gets to crowded, elongated individuals up to 1" high may form. Did you know barnacles are actually crustaceans with modified legs? Barnacles molt every once and a while, but their hard shell keeps on growing. They feed with their modified legs, called cirri.
Habitat: Rock shores, mussel beds; high intertidal zone to subtidal waters.
Range: Pacific Coast.
California Beach Flea
Megalorchestia californiana
Image Credit: iNaturalist.org
Size: 0.3" across
Diet: Seaweed rotting on the beach.
Description: a small shrimp-like creature that comes out at night to scavenge on dead seaweed and carrion. It has bright red antenna and a grey/light orange body. It is fairly common at sandy beaches, from the high tide mark to the splash zone. It is not considered a sea creature, but requires wet sand to live in. It is not related to fleas; it is a crustacean.
Habitat: Sandy beaches among seaweed or buried up to 1' under sand. Above high tide line.
Range: Oregon to Los Angeles.
Leather Star
Dermasterias imbricata
Size: 12" in diameter
Diet: algae, echinoderms
Description: 5 legs, velvet red with orange spots. Smells like garlic when disturbed. It usually lives out in the open ocean. It's diet consists of intertidal algae and creatures such as other sea stars and sea urchins. In turn is eaten by bigger sea stars. It can emit a garlic like smell to deter predators.
Habitat: rocky low intertidal zones to subtidal areas.
Range: Alaska to Mexico.
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