Species accounts

Velcro sea star

Novodinia antillensis

ORDER Brisingida

FAMILY Brisingidae

TAXONOMY

Novodinia antillensis Rowe, 1989.

OTHER COMMON NAMES None known.

PHYSICAL CHARACTERISTICS

The sea star has between 10 and 14 arms with rows of spines and teeth-like pedicellaria. Arms are long and thin. Red brick coloration.

DISTRIBUTION

Atlantic Ocean, West Indies down to depths of 1,970-2,625 ft (600-800 m).

HABITAT

Found attached to hard substratum with steeply sloping rocky surfaces; under cliffs. Prefers areas where current speeds are relatively strong. Often associated with large semi-sedentary filter-feeding animals such as large sponges, sea fans, and stony corals.

BEHAVIOR

Semi-sedentary. Spiny arms and pedicellaria act like Velcro® by sticking the sea star to virtually any surface.

FEEDING ECOLOGY AND DIET

An opportunistic suspension-feeder. Characteristic arm posture creates a basket-like appearance as arms extend into the water column and their tips curl inwards over its mouth, providing maximum exposure to currents. Food is captured as it becomes impinged on the array of arm spines and hook-like structures adapted to piercing and gripping objects. Feeds on planktonic crustaceans such as copepods, mysids, and amphipods. Remain relatively inactive whilst in the feeding posture, but slowly bend their arms to envelope captured prey.

REPRODUCTIVE BIOLOGY

Little known about its life-history. Sexual reproduction.

CONSERVATION STATUS Not listed by the IUCN.

SIGNIFICANCE TO HUMANS None known. ♦

Northern Pacific Sea Stars

Northern Pacific sea star

Asterias amurensis

ORDER Forcipulatida

FAMILY

Asteriidae

TAXONOMY

Asterias amurensis Lutken, 1871.

OTHER COMMON NAMES

English: Flatbottom sea star, Amur sea star.

PHYSICAL CHARACTERISTICS

Diameter of 16-20 in (40-50 cm), with five arms that are distinctly turned up at the tips. Colors can include rosy brown, ochre and yellowish brown, red, and purple. The underside is very flat. Skin covered with numerous unevenly arranged small spines with jagged ends.

DISTRIBUTION

Far East, Russia, Korea, Japan, China, Alaska (north and south of the Alaska Peninsula), and ranges from British Columbia, Canada, and the northern Pacific down to a depth below 820 ft (250 m).

HABITAT

Found in shallow water on sheltered coasts. It can tolerate a range of temperatures (45°F [7°C] and 72°F [22°C]) and salini ties, which is unusual in many sea stars; hence is also found living in estuaries. Found on sandy, mud and rock sediments, among stones and algae thickets.

BEHAVIOR

Forms dense spawning aggregations, where the females have been observed lifting themselves above ground on their rays and release the eggs between the arms while the male sea star crawls beneath. Polychaete Actonoe has a symbiotic relationship with the sea stars and serves to clean its surface of unwanted microorganisms.

FEEDING ECOLOGY AND DIET

A generalist feeder. Diet includes scallops, oysters, mussels, shrimp, and even other echinoderms. Juvenile king crab Par-alithodes shelter between its arms, presumably for protection against predators. Feeds by using its tube feet and arms to pull apart the shells of its prey before everting its stomach.

REPRODUCTIVE BIOLOGY

Sexual reproduction. Spawning geographically variable; in Russia, June-July and September, and in Australia, July-October. Estimated 20 million eggs are released, and develop into free-living larvae.

CONSERVATION STATUS Not listed by the IUCN.

SIGNIFICANCE TO HUMANS

Accidentally introduced into southeastern Australia and Tasmania, causing extensive commercial and ecological damage. ♦

Australian Kelp Forests Distribution

Ocher star

Pisaster ochraceus

ORDER Forcipulatida

FAMILY

Asteriidae

TAXONOMY

Pisaster ochraceus Brandt, 1835.

OTHER COMMON NAMES

English: Purple sea star.

PHYSICAL CHARACTERISTICS

Large central disc with stout tapering arms, varying from four to seven, but usually five. Size variable but can reach 11 in (28 cm). Commonly yellow, orange, brown, and purple in color. Body covered with numerous small white spines.

DISTRIBUTION

Pacific coast from Alaska to California and down to a depth of 328 ft (100 m).

HABITAT

Intertidal rocky shores exposed to strong wave action; predator of kelp forests. Also found inhabiting tide pools at low tide.

BEHAVIOR

Keystone predator because it has impact on its marine community that is disproportionately large. Can withstand 50 hours exposed to air if among moist algae.

FEEDING ECOLOGY AND DIET

Feeds mainly on the mussel Mytilus californinus, although can feed on other bivalves, snails, limpets, and chitons. Uses tube feet to pull apart shells and everts stomach to digest soft tissue. Few predators, but some are eaten by sea otters and gulls.

REPRODUCTIVE BIOLOGY

Sexual reproduction, shedding eggs and sperm into water column. Spawn between April and May. Free-swimming larvae that feed on small planktonic organisms until they settle out on rocks. Can regenerate arms.

CONSERVATION STATUS Not listed by the IUCN.

SIGNIFICANCE TO HUMANS None known. ♦

Sunflower star

Pycnopodia helianthoides

ORDER

Forcipulatida

FAMILY

Asteriidae

TAXONOMY

Pycnopodia helianthoides Brandt, 1835.

Mytilus ReproductionReproduction Biology

OTHER COMMON NAMES English: Sun star, twenty-rayed star.

PHYSICAL CHARACTERISTICS

Adults usually have between 10 and 24 arms, while juveniles have only 5. One of the largest and heaviest sea stars; sizes can range between a radius of 16 in (40 cm) and 35 in (90 cm). Color variable from pink, purple, brown, red, orange, or yellow. A broad central disc and armed with over 15,000 tube feet. Skeleton has few ossicles, so the species has a soft and flexible body wall ideal for stretching mouth to accommodate large prey.

DISTRIBUTION

Northeast Pacific coastal waters. Found inhabiting the intertidal and subtidal zones from Alaska to California down to a depth of 1,640 ft (500 m).

HABITAT

Commonly found in dense seaweeds in low intertidal zones on rocky shores because their fragile bodies need the support of surrounding water.

BEHAVIOR

Solitary. A fast-moving predator that can reach speeds of 5 ft (1.6 m) per minute. When two individuals meet, they display aggressive or combative behavior.

FEEDING ECOLOGY AND DIET

Feeds on bivalves, polychaetes, chitons, snails, crabs, sea cucumbers, sea urchins (e.g., Strongylocentrotuspurpuratus), sand dollars, sea stars (e.g., Leptasterias), and dead or dying squid when seasonally available. Uses sucker feet when capturing prey and swallows whole, although has the ability to partly evert stomach. Main predator is the king crab Paralithodes.

REPRODUCTIVE BIOLOGY

Sexual reproduction. Shed eggs and sperm into water column. Spawn from March to July, peaking in May and June. Planktonic larvae stage lasts between 2 and 10 weeks. Have the ability to regenerate arms.

CONSERVATION STATUS Not listed by the IUCN.

SIGNIFICANCE TO HUMANS None known. ♦

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Responses

  • kaarina
    Where do the northern pacific sea star come from?
    6 years ago

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