Starfish or sea stars are star-shaped echinoderms belonging to the class Asteroidea. Common usage frequently finds these names being also applied to ophiuroids, which are correctly referred to as brittle stars or basket stars. Starfish are also known as asteroids due to being in the class Asteroidea. About 1,900 species of starfish live on the seabed in all the world's oceans, from warm, tropical zones to frigid, polar regions. They are found from the intertidal zone down to abyssal depths, at 6,000 m (20,000 ft) below the surface.
The crown-of-thorns starfish, Acanthaster planci, is a large starfish that preys upon hard, or stony, coral polyps (Scleractinia). The crown-of-thorns starfish receives its name from venomous thorn-like spines that cover its upper surface, resembling the biblical crown of thorns. It is one of the largest starfish in the world.
The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide. This area can include several types of habitats with various species of life, such as seastars, sea urchins, and many species of coral with regional differences in biodiversity. Sometimes it is referred to as the littoral zone or seashore, although those can be defined as a wider region.
Kina is a sea urchin endemic to New Zealand. This echinoderm belongs to the family Echinometridae and it can reach a maximum diameter of 16–17 cm.
Asterias amurensis, also known as the Northern Pacific seastar and Japanese common starfish, is a seastar found in shallow seas and estuaries, native to the coasts of northern China, Korea, far eastern Russia, Japan, Alaska, the Aleutian Islands and British Columbia in Canada. Two forms are recognised: the nominate and formarobusta from the Strait of Tartary. It mostly preys on large bivalve molluscs, and it is mostly preyed on by other species of starfish. Population booms in Japan can affect the harvest of mariculture operations and are costly to combat.
Mediaster aequalis is a species of sea star in the family Goniasteridae. It is native to the west coast of North America, ranging from Alaska to California. It is found in various habitats including beaches during very low tides, and at depths down to about 500 m (1,600 ft). Also known as the vermilion sea star, it is the type species of the genus Mediaster and was first described in 1857 by the American zoologist William Stimpson.
The common starfish, common sea star or sugar starfish is the most common and familiar starfish in the north-east Atlantic. Belonging to the family Asteriidae, it has five arms and usually grows to between 10–30 cm across, although larger specimens are known. The common starfish is usually orange or brownish in color, and sometimes violet; specimens found in deeper waters are pale. The common starfish is found on rocky and gravelly substrates where it feeds on mollusks and other benthic invertebrates.
The Davenport Tide Pools are located just past the town of Davenport, California in the United States. They are located off Davenport Landing, which is a street off Highway 1. The tide pools are unique due to the ridges that run up and down the tide pools, allowing for different organisms to live close, even though in a normal habitat they would be unable to do so. The Beach is open sunrise to sunset, and is day use only.
Calliostoma ligatum, common name the blue top snail, is a small prosobranch trochid gastropod mollusk in the family Calliostomatidae, the Calliostoma top snails.
Pisaster brevispinus, commonly called the pink sea star, giant pink sea star, or short-spined sea star, is a species of sea star in the northeast Pacific Ocean. It was first described to science by William Stimson in 1857. The type specimen was collected on a sandy bottom, 10 fathoms (18 m) deep, near the mouth of San Francisco Bay.
Pisaster ochraceus, generally known as the purple sea star, ochre sea star, or ochre starfish, is a common seastar found among the waters of the Pacific Ocean. Identified as a keystone species, P. ochraceus is considered an important indicator for the health of the intertidal zone.
The marine snail Norrisia norrisii is a medium-sized gastropod mollusk within the family Tegulidae. It has several common names, including Norris's top snail, Norris's topsnail, norrissnail, smooth brown turban snail, or kelp snail. It was first described by G.B. Sowerby I under the name Trochiscus norrisii.
Dendraster excentricus, also known as the eccentric sand dollar, sea-cake, biscuit-urchin, western sand dollar, or Pacific sand dollar, is a species of sand dollar in the family Dendrasteridae. It is a flattened, burrowing sea urchin found in the north-eastern Pacific Ocean from Alaska to Baja California.
Leptasterias hexactis is a species of starfish in the family Asteriidae, commonly known as the six-rayed star. It is found in the intertidal zone of the western seaboard of the United States. It is a predator and is unusual among starfish in that it broods its eggs and young.
Evasterias troschelii is a species of starfish in the family Asteriidae. Its common names include the mottled star, false ochre sea star and Troschel's true star. It is found in Kamchatka and the north western coast of North America.
Margarites pupillus, common name the puppet margarite or the little margarite, is a species of sea snail, a marine gastropod mollusk in the family Margaritidae, the turban snails.
Parvulastra vivipara, the Tasmanian live-bearing seastar, is a tiny, uniformly orange-yellow seastar, up to 15 mm (0.6 in) across. The species usually has five short arms and is a rounded, pentagon shape. Morphological variation is common and three, four or six arms are occasionally present. It is endemic to coastal waters in southeast Tasmania.
Acanthopleura echinata is a Southeast Pacific species of edible chiton, a marine polyplacophoran mollusc in the family Chitonidae, the typical chitons.
Anasterias antarctica, commonly called the Cinderella starfish, is a species of starfish in the family Asteriidae. It is found in coastal waters in the Southern Ocean and around Antarctica.
Rathbunaster is a monospecific genus of sea stars belonging to the family Asteriidae. The genus name was given by Fisher as a honorific of the starfish biologist Richard Rathbun of the Smithsonian Institution. He originally ranged this genus under the family Pycnopididae, synonymous with Asteriidae.
