Field guide -- 17 species
Common residents of the Orange County rocky shore, sorted from the driest rock to the lowest pools. Use the filter to see one zone at a time.
Littorina keenae
A gray-brown snail about the size of a pea, clustered in cracks well above the water. It can survive for weeks out of the sea by sealing itself shut.
Field tip: Look high. Most people walk right past them on the dry rock.
Chthamalus spp.
Small white volcano-shaped shells crusting the rock. Each one is a shrimp-like animal lying on its back, kicking food into its mouth with feathery legs.
Field tip: Watch a submerged patch closely and you will see the legs flick out.
Pachygrapsus crassipes
Square-bodied crab, dark green to purple with fine stripes across the shell. Fast, wary, and almost always heading sideways into a crack.
Field tip: Sit still for a minute. They come back out once they decide you are scenery.
Lottia gigantea
The largest limpet on the coast. Each one grazes a private patch of algae around its home scar and will push other limpets out of its territory.
Field tip: Do not pry limpets off. Their grip is their life -- a removed limpet often cannot reattach.
Pollicipes polymerus
Clusters of leathery stalks topped with white plates, usually on wave-battered rock right alongside mussel beds.
Field tip: Find them on the most exposed, surf-facing rocks. They like rough water.
Mytilus californianus
Dense blue-black beds that blanket the mid zone. A single mussel bed can shelter hundreds of other species in the spaces between shells.
Field tip: Peer into the gaps between mussels -- worms, tiny crabs, and snails hide in there.
Anthopleura elegantissima
Small green-and-pink anemones packed shoulder to shoulder. They clone themselves by splitting, and neighboring clone groups fight along their borders.
Field tip: Out of water they close up and cover themselves in shell bits to stay damp. Step around them, not on them.
Tegula funebralis
A chunky black snail, often with a worn purple tip. Extremely common, and often wearing a smaller hitchhiking snail or limpet on its back.
Field tip: If a turban snail is walking oddly fast, flip your view -- it may be a hermit crab inside.
Pagurus samuelis
A small hermit crab living in borrowed snail shells, often black turban shells. Look for bright blue bands on the walking legs.
Field tip: They trade shells constantly. Leave empty shells on the beach -- someone needs them.
Pisaster ochraceus
Thick-armed sea star in purple, orange, or brown. A keystone predator: it eats mussels and keeps them from taking over the whole shore.
Field tip: Count the arms and check the color, but leave it attached. Pulling a star off the rock can tear its tube feet.
Anthopleura xanthogrammica
A solitary anemone up to the size of a dinner plate, glowing green from algae living inside its tissue.
Field tip: Find them in pools and channels that stay full of water. They are stunning open and underwater.
Oligocottus maculosus
A small, mottled fish that matches the bottom of the pool almost perfectly. Can find its way home to the same pool after being moved.
Field tip: Stare at a pool for a full minute without moving. The bottom will start to swim.
Strongylocentrotus purpuratus
Bright purple spheres of spines, often wedged into pits they grind into the rock over years.
Field tip: Their spines are not venomous, but they do break off in skin. Look, do not grab.
Patiria miniata
A flat, webbed sea star with short arms, in red, orange, purple, or mottled colors. A scavenger that eats almost anything.
Field tip: Usually found in deeper pools at the lowest tides. Patterns vary wildly -- no two look alike.
Aplysia californica
A large, soft sea slug in reddish-brown with ear-like tentacles. When disturbed it can release a cloud of purple ink.
Field tip: Do not lift or squeeze it. Inking costs it energy and it gains nothing from being handled.
Flabellinopsis iodinea
A vivid purple nudibranch with orange tufts, usually smaller than your thumb. One of the most photographed animals on the coast.
Field tip: Bring a phone with a decent zoom. They are tiny, delicate, and easy to crush.
Octopus bimaculoides
A small octopus with a blue eyespot ringed in dark color below each eye. Hides in crevices and rarely comes out during the day.
Field tip: Do not handle. Like all octopuses it can bite, and it does not need the stress.
Species ranges overlap, so many animals carry more than one zone tag. Names follow common usage in Southern California field guides.
Low Tide Club