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Sea stars

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Biscuit sea star / Pentaginaster duberi / Family Goniasteridae
Asteroid sea star / Linckia laevigata / Family Ophidiasteridae

Sea stars are probably the best-known family of echinoderms.

Sea star physiology

Sea stars come in all shapes and sizes. They are commonly recognised as stars and come on many different colours, the most common being yellow, red, orange and pink. Some cone in one colour while others come in many different colours. Sea stars have tube feet located on the underside. The mouth is also found on the bottom of the body. Their tube feet are not obvious because they are limited to grooves on the underside of the animal. Most sea stars have five arms with at eye at each end. This eye sees only light and darkness. If one of these arms are lost, another one can be grown back.

Habitat

Some sea stars live on the ocean floor while others live around the coral reefs.

Reproduction

Many sea stars are able to reproduce asexually when parts of their bodies break off and grow. In some cases the leg of a sea star will simply 'walk away' from the rest of the body. Some sea stars reproduce by mass spawning.

Feeding

Sea stars feed on a variety of foods ranging form algae and detritus, to living coral polyps.

Threats

Most sea stars are not currently endangered, though like all Great Barrier Reef animals, they can be affected by pollution and marked changes in water temperature.