Olympic Coast National Marine Sanctuary: Invertebrates List


Title: Olympic Coast National Marine Sanctuary: Invertebrates List
Publication Date:
July 16, 2004
Secondary Title: National Oceanic and Atmospheric Administration

Document Access

Website: External Link


National Marine Sanctuaries (2004). Olympic Coast National Marine Sanctuary: Invertebrates List. Retrieved from http://olympiccoast.noaa.gov/living/marinelife/inverts/inverts.html

Life-forms in the ocean take on a multitude of shapes and sizes, ranging from the familiar to the bizarre. Invertebrates (animals without backbones) are the largest group of animals on the planet. In the ocean, they reveal every conceivable function and design that Evolution could muster. Some are simple digestive systems encased in a gelatinous film. Others, like the octopus with its complex eyes, show powerful evolutionary development, not unlike that of mammals. Intertidal invertebrates like sea stars must live in two worlds, submerged by high tide and exposed at low. Bottom dwellers, like basket stars, live in strangely stable environment of darkness, pressure and cold.



Aggregate Anemone

(Anthopleura elegantissima)

Habitat: Rocky intertidal mid tide zone
Eats: fishes. algae, plankton, snails, crabs
Eaten by: Sea stars, nudibrachs
Moves: Usually attached.
Drying: Aggregate anemones can be hard to see in intertidal ecosystems because they are so covered by bits of shells and rocks. This protects them from the sun's heat and drying out. Reproduction: Often, they reproduce by asexual dividing. They can also sexually reproduce.

Notes: Because aggregate anemones often reproduce asexually, whole colonies can be made up of individuals with the same genes. These colonies conduct wars on other colonies that try to crowd into their territories. They release chemicals that repel invading colonies.



Fish-eating Anemone

(Urticina piscivora)

Habitat: On rocks on open coasts where there is a fair amount of current, in water 20 to 100' deep
Eats: Captures and eats shrimp and small fish
Eaten by: Leather star Dermasterias imbricata
Feeds: Stinging cells are used to immobilize their prey
Moves: Adults usually anchor to the seafloor or other structure, but are capable of moving in response to predators
Defense: Stinging cells on tentacles
Reproduction: Sexes are generally separate; the typical reproductive pattern is to spawn into the water where fertilization occurs. Anemones also divide to form new individuals.

Notes: Small fish called painted greenlings sometimes lie in fish-eating anemones, much like clownfish do in tropical anemones.



Giant Green Anemone

(Anthopleura xanthogrammica)

Habitat: Mid to low tide zone, attached to rocks.
Eats: Fishes, algae, plankton, snails, crabs
Eaten by: Nudibranchs, seastars, snails, fishes
Feeds: Paralyzes prey with stinging cells on tentacles. Swallows prey whole, spits out shell and indigestible parts.
Moves: Attaches in clusters
Defense: Stinging cells called nematocysts
Drying: Covers with shell bits and closes up
Reproduction: Reproduces both sexually and asexually (through budding). Separate sexes fertilize externally.

Notes: A green algae lives inside these anemones and give them a plant-like color. Studies show that anemones that live in caves and lack algae loose weight faster when food is not available.



Metridium Anemone

(Metridium giganteum)

Habitat: Attached to hard surfaces, low intertidal zone to 1000'
Eats: Copepods and various invertebrate larvae
Eaten by: Shaggy mouse nudibranch and leather star
Feeds: Catches prey with stinging cells on 200 tentacles around the oral disk
Moves: Larvae drift and eventually settle. Adults are usually fixed to hard surfaces.
Defense: Long threads with stinging capsules from the mouth and special tentacles defend territory against other colonies (clones) or anemone species. Can extend or flatten its body by changing its internal water pressure.
Reproduction: Anemones often divide to form new individuals. At other times males and females release sperm and eggs into the water.

Notes: To 3' tall. White, brown or tan to salmon-orange. Usually more than 200 slender, translucent tentacles crowning a smooth column. Common in dense aggregations.



Acorn Barnacle

(Balanus sp.)

Habitat: High to low tide zone; attached to rocks, shells
Eats: Plankton
Eaten by: Drill snails, seastars, worms, fishes, birds
Feeds: Sweeps plankton into mouth with feathery feet.
Moves: When they are young, they swim as plankton. Adults glue their head to something stable.
Defense: Withdraws into shell
Drying: Closes shell
Reproduction: Hermaphroditic (both male and female); internal fertilization.

Notes: The glue they use to attach themselves is one of the strongest natural adhesives known. It is used in human dentistry!



Gooseneck Barnacle

(Pollicipes polymerus)

Habitat: Often in thick clusters on exposed coast in areas subjected to strong wave action, mid-intertidal zone and lower.
Eats: Plankton
Eaten by: Gulls, humans (exported from North America to Europe)
Feeds: Modified legs (cirri) sweep through the water like a net to collect tiny planktonic food.
Moves: Larvae drift and settle; mature barnacles are fixed.
Defense: Resilient stalks are tough enough to withstand the forces tossing them in the surf. An exoskeleton with 5 large plates and many small plates protects the animal inside.
Drying: Plates close at low tide to protect the animal from drying out.
Reproduction: Reach sexual maturity at 80 days. Males may become females (or vice versa) at any time. To reproduce, the male must locate a female close enough for his penis to reach, as barnacles are unable to move from their substrate. The penis, however, can reach up to 20 times the length of the barnacle's body.

Notes: Often found in close association with the California mussel.




(Lined Chiton: Tonicella lineata)

Habitat: Mid to low tide zone; attached to rocks
Eats: Bacteria, algae
Eaten by: Gulls, seastars, crabs, fishes, anemones
Feeds: Grazes with raspy tongue-like "radula"
Moves: Glides slowly on foot; most active at night.
Defense: Clamps to rocks, or rolls in a ball if dislodged.
Drying: 8 interlocking plates enable it to conform to uneven rock surfaces and seal tightly.
Reproduction: Separate sexes; external fertilization

Notes: Carries "hitchhikers"; hydroids, byozoans, algae, barnacles, limpets, sponges, others. Largest species in the world is found in the Pacific Northwest Region: the gumboot chiton.



Razor Clams

(Siliqua patula)

Habitat: Sand beaches; low tide zone to sub-tidal zone
Eats: Filters the water for plankton
Defense: Buries itself quickly into the sand.

Notes: Razor Clams have been known to live 18 years, though their average life-span is five years. Razor Clams have been found up to one-half mile offshore. Domoic acid collects in the tissue of Razor Clams. This naturally occurring by-product of phytoplanktons is poisonous to humans. It appears that domoic acid rates are increasing and human impacts may be the cause. Scientists are studying this relationship.



Dungeness Crab

(Cancer magiste)

Habitat: Prefers sandy offshore waters to 750', but younger crabs can be found in the intertidal zone, often in eelgrass or in the bottom of sandy tidepools
Eats: Shrimp, small clams, oysters, worms, fish, barnacles
Eaten by: Humans, giant Pacific octopus
Feeds: Uses claws to capture and tear prey. Mouth parts are used for biting and grinding.
Moves: 4 pair of walking legs
Defense: Hard shell; buries itself in the sand after molting
Drying: Buries itself in the sand during low tide
Reproduction: Separate sexes. Mating takes place just after molting. Female carries up to 2.5 million eggs under her broad abdomen until the larval crabs hatch.

Notes: Important commercial, recreational and Native food fishery. Molts up to 15 times in its life. Molted crab shells that wash up on ocean beaches often lead to erroneous reports of crab mortality.



Green Crab

(Carcinus maenas)

Habitat: Rocky intertidal, low to subtidal zone
Eats: Detritus, other crabs
Defenses: Pinchers

Notes: Green crabs are an invasive species from Europe. They prey on other crabs. Ecologists are closely monitoring their population growth because they are both an ecological and economic threat to Dungeness and other crab species. So far, they have been found in Gray's harbor to the south of the Sanctuary and Vancouver Island to the north. They were accidentally introduced to the Pacific Northwest.

To identify Green Crabs, remember, 5-3-5. They have five lobes on the outside of their left eye, three lobes between their eyes and five lobes on the outside of their right eye. Although it is called the green crab, it can be orange or red as well. Color is not a good way to identify the green crab in general because many crabs can have a greenish color.

If you find a green crab matching this description, call the Washington Department of Fish and Wildlife at 360-796-4601.



Hermit Crab

(Pangurus armatus)

Habitat: Mid tide zone; tidepools
Eats: Scavenges
Eaten by: Birds
Feeds: Uses claws to bring food to mouth
Moves: Crawls with legs.
Defense: Withdraws into shell; large claws act like a shield to block entrance.
Drying: Finds refuge in tidepools and under rocks
Reproduction: Separate sexes; external fertilization. Eggs attach to female's abdomen.

Notes: There are many different types of Hermit Crabs. They all inhabit discarded shells. May have sponges, barnacles and others "hitching" a ride on their shells.



Kelp Crab

(Pugettia producta)

Habitat: Low tide to deep waters
Eats: Brown kelp and sometimes other animals
Reproduction: Mating takes place in deeper waters in the late fall

Notes: The color of this crab closely matches the color of the kelp it eats. In the fall, adults migrate to deeper water. They return to the intertidal in December. As the kelp crab ages, it becomes increasingly carnivorous.



Purple Shore Crab

(Hemigrapsus nudus; green: H orgonerisis)

Habitat: Mid to low tide zone; under rocks
Eats: Green algae
Eaten by: Fishes, birds
Feeds: With large pincers
Moves: Scurries sideways with legs
Defense: Hides under rocks; burrows into mud
Drying: Can withstand long periods out of water
Reproduction: Separate sexes; internal fertilization. The female broods eggs between her tail and abdomen

Notes: What looks like a dead crab, may just be the discarded outgrown shell- the molt.



Puget Sound King Crab

(Lopholithodes mandtii)

Habitat: On rocky reefs in currents, shallow subtidal to 450'
Eats: Feeds on sea urchins, starfish and other echinoderms and has also been observed eating sea anemones
Eaten by: Giant Pacific octopus
Feeds: Uses claws to capture and tear prey. Mouth parts are used for biting and grinding. Fingers of the smaller left claw are spoonlike and close tightly, making it useful for scraping and cropping sessile organisms from the surface rocks, while the much larger right claw is armed with molars for crushing hard-shelled prey.
Moves: 3 pair of walking legs
Defense: Coloration blends in with other organisms encrusting the rocks in their habitat, unusual carapace shapes also make them hard to distinguish from their surroundings.
Drying: Not found in the intertidal zone
Reproduction: Adults concentrate in relatively shallow water during the late winter and spring to breed. Mating takes place just after molting.

Notes: One of the largest crabs on our coast; carapace width to 12 inches (300 mm) or more.




(Florometra serratissima)

Habitat: On rock walls in currents, 30 to 3,300' deep
Eats: Plankton
Eaten by: Basket stars
Feeds: Feathery arms capture food, and the cilia and tube feet transport it along grooves to the mouth on the upper side of the cupped plate.
Moves: Can move using the cirri or swim by using the rays
Defense: Crinoids' arms fragment quickly when disturbed by predators, and are regenerated.
Drying: Not found in the intertidal zone
Reproduction: Crinoids reproduce sexually by the males releasing their sperm and the females releasing their eggs into the current where they will develop into a bottom-dwelling non-feeding larval stage, and within 10 to 16 months will be able to reproduce. In some cases the female of the species has been known to temporarily brood the larva.

Notes: Living crinoids are small relative to some fossil species that had stalks 80' long!



Sea Cucumber

(Cucumaria miniata)

Habitat: Low tide zone
Eats: Detritus (dead material) and plankton
Eaten by: Fishes and crabs
Feeds: Mucus-coated tentacles "mop up" plankton and other materials. Tentacles are then licked clean.
Moves: Crawls with tube feet
Defense: Retracts tentacles. Tightly lodges itself between rocks. Can spit out its own guts and regenerate its internal organs.
Drying: Nestles between rocks, in moist places has thick skin.
Reproduction: Separate sexes, external fertilization.



Cup Coral

(Balanophyllia elegans)

Habitat: On shady sides and under rocks or boulders, low intertidal zone to 70 feet deep.
Eats: Plankton
Eaten by: Crabs, sea stars
Feeds: Feeding is accomplished with small, nearly transparent tentacles with stinging cells and a mouth which opens to trap food.
Moves: Larvae are free swimming; adults are attached
Defense: Stinging cells in tentacles
Drying: Tentacles can retract into the stony cup
Reproduction: Sexes are separate, with eggs fertilized and developing in the female's gastrovascular cavity, releasing worm-like orange larvae in spring and summer

Notes: No other orange stony coral is found intertidally in the Pacific Northwest.



Keyhole Limpet

(Diodora aspera)

Habitat: Low to sub-tidal zone; attached to rocks
Eats: Algae
Eaten by: Seastars, birds
Feeds: Scrapes algae off the rocks with radula
Moves: Moves with one foot; most return to a particular "home" during the day.
Defense: Clamps to rocks using 70 pounds of force.
Drying: Active at night, when covered with water
Reproduction: Separate sexes; external fertilization

Notes: Bryozoans, small barnacles and algae may grow on shells. This limpet can cover its shell with its mantle (a piece of its body). This can prevents their predator, the sea stars, from being able to attach their tube feet.



Squat Lobster

(Munida quadraspina)

Habitat: On or swimming above mud bottom; subtidal to 4800'. Usually seen on rock faces or cobble in low current, slightly silty areas.
Eats: Diet consists primarily of detritus and small planktonic organisms.
Eaten by: Octopus, seals, sea otters and other marine mammals
Feeds: Claws are used for catching and tearing food.
Moves: Three pair of walking legs; also able to swim over the sea floor.
Defense: Exoskeleton provides some protection from predation. Legs may be dropped off if seized by a predator or badly damaged, and regrown during molting.
Reproduction: Eggs are fertilized externally shortly after mating. Females brood eggs on their pleopods, caring for them and periodically shaking the egg mass to aerate them.

Notes: A fifth pair of legs are greatly reduced in size and kept folded in the gill chamber; the tiny claws and brushes on the tip are used to clean the gills and other parts of the body.



California Mussel

(Mytilus californianus)

Habitat: Mid tide zone; attached to rocks, or shells
Eats: Plankton
Eaten by: Seastars, ribbon worms, drill snails, crabs, birds, fishes, sea otters, and humans. Human should be cautious when eating mussels because they can cause Paralytic Shellfish Poisoning.
Feeds: Filter-feeds; traps plankton with mucus
Moves: Attaches with thin, black "byssal" threads".

Notes: Mussel beds create homes for other animals. In one study, a plot the size of one square foot yielded 4,711 individuals from 22 different species.



Giant Red Dendronotid Nudibranch

(Dendronotus rufus)

Habitat: On rocks and algae in shallows
Eats: May at times feed on the scyphistoma (larval) stage of some jellyfish.
Eaten by: Sea stars prey on egg masses
Moves: Crawls on a muscular foot
Defense: Protective coloration helps it blend in with the rocky shoreline
Reproduction: Nudibranchs are hermaphroditic, possessing both male and female sex organs. Mating involves the simultaneous exchange of sperm with the subsequent fertilization of each animal's eggs. Eggs are deposited in coils on rocky structure in shallow water



Orangepeel Nudibranch

(Tochuina tetraquetra)

Habitat: On rocks, shallow subtidal from Alaska to southern California where there is little light and little water movement
Eats: hydroids, soft coral and orange sea pens
Eaten by: Rarely attacked or eaten by other animals; Kuril Indians eat it raw or cooked.
Feeds: Nudibranchs have a ribbon of teeth called a radula, adapted to match the favorite food source of the individual nudibranch.
Moves: Crawls along the seafloor on a muscular foot
Defense: Secrete toxic chemicals to defend themselves. One defensive strategy that nudibranchs use is called 'cryptic coloration', otherwise known as camouflage. Many types of nudibranchs are colored to match their surroundings (which is usually also their food source) so they blend into their surroundings and are difficult for predators to spot.
Drying: Not found in the intertidal zone
Reproduction: Nudibranchs are hermaphrodites, with individuals capable of both making and fertilizing eggs. The mating pair cross-fertilize each other, and then each lays its eggs encased in a soft, distinctively looped gelatinous matrix. Eventually these disintegrate, and the larvae hatch and swim away.

Notes: Largest nudibranch in the world, with adults reaching 12 inches (300 mm). Also found in Russia where it is called tocni and eaten raw or cooked.



Sea Lemon Nudibranch

(Anisodoris nobilis)

Habitat: Found on pilings, around docks, and on rocks below the low tide line, intertidal to 750'. Look for them tucked away under fronds of seaweed on rocky shores.
Eats: Feeds on tennis ball, yellow encrusting, peach ball, and other sponges
Eaten by: Fish have been observed nibbling on rhinophores and gill plumes.
Feeds: Rhinophores sense chemicals in the water to help find food.
Moves: On a muscular foot
Defense: Protective coloration; also emits a strong odor if provoked, thought to dissuade predators from eating them
Reproduction: Hermaphrodite; both male and female. Lays ribbons of yellow eggs.

Notes: One of the largest sea slugs of the Pacific Coast, growing to 4" intertidally and up to 8" subtidally




(Octopus dofleini)

Habitat: Subtidal in rock caves; tidepools
Eats: Mollusks, crabs, fishes
Eaten by: Large fishes, wolf eels, crabs
Feeds: Attacks prey with arms; parrot-like beak covered with poison kills and digests prey.
Moves: Propels by expelling water through siphons. Crawls with tentacles.
Defense: Fast swimmer, and can squirt an ink "fog screen". Can change color to camouflage to the surroundings. Uses tentacles for fighting.
Reproduction: Separate sexes; internal fertilization. Mother protects eggs for 4 months.

Notes: Octopus have a highly developed brains and eyes. The world's largest species live in the Pacific Northwest Region and can grow to 30 feet long and weigh 600 pounds.



Sea Pen

(Ptilosarcus gurneyi)

Habitat: Anchored in sand-mud, in substrate at least 3" deep; intertidal to 330'
Eats: Detritus, zooplankton and possibly phytoplankton
Eaten by: Eaten by striped nudibranchs, diamond back tritons, and other nudibranchs; and by several sea stars including leather, spiny red, rose, vermillion, and other sea stars.
Feeds: Each plume is comprised of paired branches, each with numerous feeding polyps. The fleshy "quill" pumps water throughout the colony.
Moves: Larvae are free swimming; adults remain anchored to the substrate
Defense: They can retract fully into the sea bottom.
Reproduction: Reproduction either by sexual or asexual means. The animals free-spawn and produce planktonic larvae that develop in the water column.

Notes: Sea pens are octocorals; each polyp has 8 tentacles. This species of sea pen is bio-luminescent in the dark when disturbed.



Smooth Bay Shrimp

(Crangon stylirostris)

Habitat: Low tide zone; sandy beaches
Eats: Small crustaceans and small clams
Eaten by: Large fishes, octopuses, anemones, crabs, humans
Feeds: With specialized feeding appendages
Moves: Swims very quickly
Defense: Spines on upper body
Reproduction: Separate sexes; internal fertilization. Eggs attach beneath tail of females.

Notes: Antennae are chemical and tactile sensors. Commercially important.



Spot shrimp

(Pandalus platyceros)

Habitat: Rocky bottom, intertidal to 1600'
Eats: Zooplankton, worms, and small fish, also polychaetes, small crustaceans such as amphipods and euphausiids, limpets, and other shrimp.
Eaten by: Humans; caught in traps or pots from California to Alaska
Feeds: Moves its antennae in the water current to detect movement; grabs prey with its tiny pinchers.
Moves: Free-swimming or scrounge along the rocky or muddy bottom
Reproduction: Spot shrimp are protandric hermaphroditic meaning that each individual initially matures as a male and then passes through a transition stage to become a female. Spot shrimp usually live for about 4 years, starting their lives as males and maturing at one year of age. They function as mature males for 2 years and then transform into females in their final year of life.



Lewis's Moonsnail

(Euspira lewisii)

Habitat: Common on sand, intertidal to 165'
Eats: Littleneck, butter, truncated softshell and Pacific gaper clams
Eaten by: Sunflower star
Feeds: The moonsnail burrows and feeds on clams, drilling into shells and cutting the flesh of the clam with its tooth-like radula. An adult moonsnail consumes about one clam every four days.
Moves: Crawls across the seafloor on a muscular foot
Defense: Withdraws into its shell if threatened.
Reproduction: Lays its eggs in a distinctive sand collar, molded by the shell curvature as it is released from the snail's body. Many small eggs are distributed in a central jelly layer, coated with sand of both sides. Eggs hatch out of the collar in about six weeks.




(Cliona species)

Habitat: Low tide zone. Lives attached to rocks, shells, wood and kelp
Eats: Plankton
Eaten by: Nudibranchs and some sea stars
Feeds: Filter feeds
Moves: Lives attached
Reproduces: Hermaphroditic (both male and female); internal fertilization; or asexual budding.

Notes: Can be a home for other animals such as small crustaceans and worms. Secretes an acid to dissolve shells. This helps to turn shells into sand. Some sponges have symbiotic algae living in them.



Basket Star

(Astroboa nuda or Gorgonocephalus eucnemis)

Habitat: On rocks in current; subtidal to 6,600 feet
Eats: Plankton, detritus
Feeds: Captures food by extending a forest of arms into the currents
Moves: Most active at night
Defense: Arms break off readily and can be regenerated
Drying: Not found in intertidal areas
Reproduction: Shed eggs and sperm into the water; can reproduce asexually by division

Notes: The basket stars are a specialized type of brittle stars. They have a series of complexly branched arms which are used to catch plankton. 5 arms branching into thousands of branchlets. White to tan, beige, orange-red, pink mottling.



Bat Star

(Asterina miniata)

Habitat: On rocks, sand and mud, on exposed coasts, not in surf; intertidal to 960'
Eats: Feeds on plants and animals, both dead and alive. Algae and kelp are favorite foods.
Feeds: Bat stars have sensors at the end of each arm that sense light and detect prey. When a bat star finds a food item it extends its stomach out of its mouth and wraps it around the food of its choice, digesting externally before swallowing.
Moves: on tube feet
Defense: Exoskeleton made of plates joined by connective tissue protect the bat star's vital organs.
Reproduction: Bat stars reproduce by spawning. The male broadcasts sperm and the female broadcasts eggs from pores near the bases of their arms. Fertilization takes place in the sea, and currents carry the young to new homes.

Notes: typically 5-6 rays, but possibly 4-9. Rough granular surface and web-footed appearance. Red, blue, yellow, green and/or brown, solid or in patterns. Abundant and common. Hosts a number of polychaete worms on the underside. Bat stars have been kept in captivity for more than 16 years and are thought to live up to 30 years.



Brittle Star

(Ophiopholis aculeate)

Habitat: Under stones, in algal holdfasts and rocky shores, low intertidal zone to 5400'
Eats: Plankton
Eaten by: China rockfish, gulls, crabs
Feeds: Scrapes minute organisms from rock with its specialized tube feet. Food then enters the stomach, which takes up most of the body cavity. Cannot extrude its stomach to feed as other sea stars do.
Moves: Brittle stars use their arms for locomotion. They do not, like sea stars, depend on tube feet. Brittle stars move fairly rapidly by wriggling their arms which are highly flexible and enable the animals to make either snake-like or rowing movements
Defense: When stressed they often shed arms, then regenerate new ones
Drying: Hides under rocks in the intertidal zone.
Reproduction: Separate sexes. Gametes are released into the water.

Notes: There are more than 2,000 species of brittle stars, sometimes called "serpent stars" because of the snakeline shape and movement of the rays.



Cushion Star

(Pteraster tesselatus)

Habitat: On rocks, subtidal 20 to 1400' deep; often in areas with strong currents
Eats: Has been observed feeding on encrusting sponges, bryozoans, hydroids, and colonial sea squirts; and less frequently on sea anemones, rock oysters, scallops, and solitary sea squirts
Eaten by: Predators include Solaster dawsoni (Morning Sunstars) and Pycnopodia helianthoides (Sunflower Star)
Feeds: A large oral opening at the center of the disc is surrounded by a sphincter-like membrane; feeds by inverting its stomach to digest food
Moves: The cushion star is mobile, but it is not an agile starfish because of the relative thickness of the disc in proportion to the length of its rays.
Defense: Releases copious amounts of thick, gelatinous mucus that serves as protection against fish and other predators
Reproduction: Breeds from early July to late August. Releases yellow or orange eggs in a long string. Fertilized eggs develop into nonfeeding larvae that pass directly into the adult without metamorphosis. This is the only sea star known to have truly direct development.

The process of reproduction is a continuous one and begins when the female pumps eggs out through the osculum. The males then spawn. The fertilized eggs float to the surface of the water. They are bright orange or yellow and measure 1.5mm in diameter. Each egg is covered with a coat of jelly, and the fertilization membrane can be seen beneath it. The egg then goes through several transformations in the plankton, and the five primordial arms appear simultaneously. Immediately, the larva sinks to the bottom and ends its planktonic life. The star can then crawl. Metamorphosis takes a total of aproximately thirty days.



Ochre Sea Star

(Purple Star: Pisaster ochraceus)

Habitat: Low tide zone; rocks
Eats: Clams, mussels, barnacles, oysters, snails, limpets, chitons
Eaten by: Gulls, sea otters
Feeds: Arms clamp to prey and force shell open. They can then place their stomach into the prey with an opening of only .1 mm. It can take 2-3 days to digest their prey.
Moves: Moves swiftly with thousands of suction-cup tube feet.
Defense: Can regenerate lost arms if part of their central disc is intact. Tweezer-like "pedicellariae" on their upper surface keep anything from settling on them and clogging the breathing ability of their skin
Drying: Thick skin prevents drying
Reproduction: Separate sexes; external fertilization

Notes: Same species may be orange, purple, burgundy, or brown. Light sensitive eyespots are on the tip of each arm.



Pacific Blood Star

(Henricia leviuscula)

Habitat: Low tide zone
Eats: Sponges and bacteria and other small particles it traps with mucus. This food is then transported up to its mouth with cilliary tracks.
Eaten by: Birds
Reproduction: Smaller females brood their young, while larger females release their eggs directly into the deeper waters. Sea Stars greatest enemies are human collectors.



Rainbow Star

(Orthasterias koehleri)

Habitat: On sand, shell to rock, very low intertidal to 800'
Eats: Feeds on the ribbed clam, rock oysters, and other bivalves; also on small snails, limpets, scallops, barnacles, tunicates and other invertebrates.
Feeds: Pushes its stomach between the shells of a clam to begin digesting its meal.
Moves: on tube feet on the underside of each ray
Defense: Calcareous plates covered with a soft layer of skin; prominent sharp spines on the dorsal surface; also able to regenerate missing rays
Reproduction: Breeds from June to August. It elevates itself on arm tips to spawn from paired gonopores. Females produce translucent orange eggs. After fertilization these develop into planktonic larvae.

Notes: Also called Painted Star or Long-armed Sea Star



Striped Sun Star

(Solaster stimpsoni)

Habitat: On rocks and other surfaces to 2000', often in the low intertidal zone
Eats: Sea cucumbers, sea squirts, tunicates and other invertebrates Eaten by: Morning sun star
Feeds: by extruding the stomach to digest food outside the body
Moves: by tube feet
Reproduction: Gametes are discharged into the water for external fertilization

Notes: The most common sunstar, it usually has 10 arms. Up to 16" in diameter



Sunflower Star

(Pycnopodia Helianthoides)

Habitat: Soft bottoms and rocky shores, subtidal to 1450'. Enters intertidal waters to forage.
Eats: Crab, sea cucumbers, snails, chitons, bivalve mollusks, purple sea urchins, other sea stars. Has been observed to feed on dead squid and dead fish.
Eaten by: Alaska king crab
Feeds: A voracious feeder, preying on many large clams and crustaceans. Often digs out butterclams and leaves pits in sandy areas. A sunflower star can swallow an entire sea urchin, digest it internally and then expel the urchin's test - its external shell.
Moves: Moves rapidly on tube feet, up to 6' a minute when hunting for food.
Defense: Arms break off readily if caught.
Reproduction: Gametes are discharged into the water for external fertilization

Notes: Largest and fastest sea star found in the Pacific Northwest, up to 40" in diameter. When young they have six arms, but as they age new arms are added until there are more than 20.



Calcareous Tube Worm

(Serpula vermicularis)

Habitat: Mid to low tide zone: attached to rocks and shells
Eats: Plankton
Eaten by: Fish nip off tentacles
Feeds: Filter-feeds with tentacles
Moves: Lives in hard white tube
Defense: Withdraws tentacles
Drying: Closes tube entrance
Reproduction: Separate sexes; internal fertilization

Notes: Tube may extend 2-3 feet. Microscopic hair-like cillia pulse in unison to draw plankton to the mouth like an automated assembly line. Mucus is secreted to grow and repair the tubes this worm lives in.



Sea Urchins

(Strongylocentrotus sp.)

Habitat: Low tide zone; on rocks
Eats: Seaweed
Eaten by: Sea otters, Seastars, crabs, gulls
Feeds: Tube feet pass seaweed to mouth; chews with a 5 pointed jaw called "Aristotle's Lantern"
Moves: Moves on tube feet and spines
Defense: Spines protect from predation. Tweezer-like "pedicellariae" keep anything from attaching to them.
Drying: Covers body with bits of shell to reflect the sun
Reproduction: Separate sexes; external fertilization

Notes: Three species; green, red and purple. The shell is called a "test". The green urchin (Strongylocentrotus droebachiensis) has the longest scientific name in the animal kingdom! Urchin populations have damaged kelp populations in areas where Sea Otters have not kept urchin populations in check.



Not yet pictured...

  • Hydrocoral
  • Hydroid
  • Aurelia Jelly
  • Fried Egg Sea Jelly
  • Lophelia
  • Dirona Nudibranch
  • Leopard Nudibranch
  • Plumerella
  • Paragorgia
  • Primnoa
  • Rock Scallop
  • Rose Star
  • Vermillion Star
Find Tethys on InstagramFind Tethys on FacebookFind Tethys on Twitter
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.