Blue sea star
Linckia laevigata
Starfish
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About
Starfish are slow-moving reef animals with a central disc and radiating arms. In this app the group includes the blue sea star, the spotted linckia, and the pillow cushion star.
How to tell it apart
The mark that settles it is the radiating-arm body plan around a central disc, unlike the round, armless shape of a sea urchin. To tell members apart, count the arms and compare colour, surface texture, and size.
Appearance
Most starfish have five arms spreading out from a central disc, though some species have six, seven, or many more. The top surface is covered in hard plates that can look flat, grainy, or spiny, and colour varies widely across the group.
Habitat
Starfish live in every ocean, from the tropics to polar waters. Most live on the seabed on sand, mud, or rock, from shallow shorelines down to very deep water.
Behaviour
Some starfish can regrow a lost arm, and a few can even regrow a whole new animal from a single arm. Regrowth can take several months.
Diet
Most starfish are generalist predators that eat small animals such as sponges, clams, and snails, though the crown-of-thorns starfish eats coral polyps. Some feed on decaying matter, and a few filter tiny food from the water.
Breeding
Most starfish have separate males and females, though a few species change sex as they grow or make both eggs and sperm. Most release eggs and sperm into the water, where they develop as plankton, though some species brood their eggs on or in their body.
Did you know?
Some starfish can regrow an entire new animal from just one detached arm, as long as part of the central disc stays attached.
Log it in Into the Blue
Describe what you saw and we name it, then keep every species you find in your Oceandex.
