City of Edmonds - Washington

Sea Stars and Relatives

Sea stars and their relatives (sea cucumbers, sand dollars and sea urchins) belong to a large group of animals called echinoderms (meaning spiny-skinned). All members of this group have calcerous plates covered by a soft layer of skin. The size of the plates varies from large and conspicuous (sea stars and sea urchins) to inconspicuous (sea cucumbers).

blood star

Henricia leviuscula

Description: Move on hundreds of small tube feet under main arms. Each tube foot has a suction cup. Mouth below central disk. Stomach extends outside mouth to digest prey. Usually bright reddish-orange. Found on rocky intertidal beaches or sandy areas near eelgrass beds. Length to 5 in (13 cm).

Food: Feeds mostly on sponges.

Reproduction: Sexes are separate. Gametes are discharged into the water for external fertilization. Young usually develop as planktonic forms.

Fun Facts: Like most other sea stars, the blood star has remarkable regenerative powers. It can regrow an arm, or even most of its body as long as a portion of the central disk remains undamaged.

ochre sea star

Pisaster ochraceus

Description: Also known as the purple sea star. Move on hundreds of small tube feet under main arms. Each tube foot has a suction cup. Mouth below large central disk. Stomach extends outside mouth to digest prey. Purple to ochre color locally. Arms are stiff and bumpy with pattern of white spines. Found on rocky beaches and pilings. A keystone species. Length to 15 in (38 cm).

Food: Feeds on beds of mussels, barnacles, chitons, snails, and limpets. Powerful arms force open shells while extruded stomach digests soft body parts.

Reproduction: Sexes are separate. Gametes are discharged into the water for external fertilization. Young usually develop as planktonic forms.

Fun Facts: Color appears dependant on water temperature when young.

mottled sea star

Evasterias troschelii

Description: Move on hundreds of small tube feet under main arms. Each tube foot has a suction cup. Mouth below small central disk. Stomach extends outside mouth to digest prey. Locally blue, gray and orange; with or without mottling. Arms are stiff and bumpy with small white spines. Found on rocky beaches and pilings, sometimes on sand. Length to 20 in (51 cm).

Food: Feeds on beds of mussels, barnacles, chitons, snails, and limpets. Powerful arms force open shells while extruded stomach digests soft body parts.

Reproduction: Sexes are separate. Gametes are discharged into the water for external fertilization. Young usually develop as planktonic forms.

Fun Facts: Scale worms often are found on the undersides of this sea star, living in a commensal relationship.

sunflower star

Pycnopodia helianthoides

Description: Spectacular sea star with up to 24 arms. Move on hundreds of small tube feet under main arms. Each tube foot has a suction cup. Mouth below central disk. Stomach extends outside mouth to digest prey. Body and arms are soft and bumpy with numerous white spines. Usually bright or dull, reddish-orange. Found on rocky intertidal beaches or sandy areas near eelgrass beds. Length to 40 in (102 cm).

Food: Varied diet of crabs, clams, scallops, sea cucumbers, sea urchins, and many other creatures, including other sea stars.

Reproduction: Sexes are separate. Gametes are discharged into the water for external fertilization. Young usually develop as planktonic forms.

Fun Facts: Sunflower sea stars are the fastest sea star, able to move underwater at the rate of 360 ft (110 m) per hour!

striped sun star

Solaster stimpsoni

Description: Move on hundreds of small tube feet under main arms. Each tube foot has a suction cup. Mouth below central disk. Stomach extends outside mouth to digest prey. Usually bright reddish-orange, with bluish gray stripes running down the middle of 10 slender arms. Rare intertidally, but common in deeper water. Locally found most often under the Ferry Dock. Length to 15 in (38 cm).

Food: Feeds on small sea cucumbers, sea squirts and other invertebrates.

Reproduction: Sexes are separate. Gametes are discharged into the water for external fertilization. Young usually develop as planktonic forms.

Fun Facts: This animal's chief enemy is the similar looking morning sun star, which feeds exclusively on other sea stars.

Six-rayed sea star

Leptasterias hexactis

Description: The only 6-armed sea star. Common but often unnoticed. Move on hundreds of small tube feet under main arms. Each tube foot has a suction cup. Mouth below central disk. Stomach extends outside mouth to digest prey. Tan to greenish gray, orange, yellow, brown, or black; often with a pattern. Found on rocky intertidal beaches or sandy areas near eelgrass beds. Length to 3.5 in (9 cm).

Food: Feeds on barnacles, limpets, mussels, chitons, sea cucumbers, and snails.

Reproduction: Sexes are separate. This unusual sea star broods its young. Spawns in winter. After eggs are laid, female will arch over the eggs, cleaning and tending them for up to two months, during which time she does not eat.

Fun Facts: These tiny sea stars take two years to reach maturity.

leather star

Dermasterias imbricata

Description: Move on hundreds of small tube feet under main arms. Each tube foot has a suction cup. Mouth below central disk. Usually mottled reddish-brown to orange. Body feels like wet leather. A slippery secretion covers the surface. Found on rocky low intertidal beaches. Length to 10 in (25 cm).

Food: Eats a variety of anemones, urchins and sea pens, as well as other small invertebrates which it swallows whole.

Reproduction: Sexes are separate. Gametes are discharged into the water for external fertilization. Young usually develop as planktonic forms.

Fun Facts: This species often is said to smell like garlic or sulphur, explaining one of its common names, the garlic star.

california sea cucumber

Parastichopus californicus

Description: The largest local sea cucumber. Moves on three rows of small tube feet along underside of body. Each tube foot has a suction cup. Mouth located at one end of body. Usually mottled reddish-orange, with lighter colored projections along the entire body. Found on low intertidal beaches in sheltered areas. Length to 20 in (51 cm).

Food: Cleans detritus with the 20 sticky feeding tentacles surrounding its mouth.

Reproduction: Sexes are separate. Gametes are discharged into the water for external fertilization. Young usually develop as planktonic forms.

Fun Facts: This species can, when trying to escape a predator, eject its internal digestive organs (which resemble wet spaghetti noodles) in order to distract the attacker while the cucumber moves away. Once safe, the animal begins the process of regrowing those organs.

orange sea cucumber

Cucumaria miniata

Description: A medium-sized sea cucumber. Orange body with rows of brownish-red tube feet on which it moves. Each tube foot has a suction cup. Mouth located at one end of body. Found on low intertidal beaches under rocks with only a portion of the body exposed. Length to 8 in (20 cm).

Food: Cleans detritus with the 10 sticky feeding tentacles surrounding its mouth.

Reproduction: Sexes are separate. Gametes are discharged into the water for external fertilization. Young usually develop as planktonic forms.

Fun Facts: Researchers have found that the blood of this sea cucumber is very similar to that of trout and other fish.

white sea cucumber

Eupentacta quinquesemita

Description: A small-sized sea cucumber. White to cream colored body with rows of small tube feet on which it moves. Each tube foot has a suction cup. Mouth located at one end of body. Found on low intertidal beaches or subtidally, under rocks with only a portion of the body exposed, or among mussels or tube worms. Length to 3.5 in (9 cm).

Food: Cleans detritus with the 10 sticky feeding tentacles surrounding its mouth.

Reproduction: Sexes are separate. Gametes are discharged into the water for external fertilization. Young usually develop as planktonic forms.

Fun Facts: This sea cucumber has a lot of natural enemies, including the sunstars, sunflower stars, and even the tiny six-rayed sea star, which eats the sea cucumber young.

green sea urchin

Strongylocentratos droebachiensis

Description: Long mobile spines connected to a hemispheric shell called a 'test'. Each spine is attached to the test with a ball and socket joint. Long tube feet reach out beyond the spines. Found on rocky low intertidal beaches and kelp beds. Major predators locally are sea stars, river otters and fish. Diameter to 3.5 in (9 cm).

Food: Feeds on detritus, sea lettuce and kelp with its five-part pinching jaw (located on the underside).

Reproduction: Separate sexes. Eggs and sperm broadcast into the water. Young sea urchins live under the protective spiny shields of the adults.

Fun Facts: Sea urchin gonads are eaten as a delicacy in Japan.