Facts about this animal
The Common Starfish is variably coloured and may be orange, reddish, yellowish brown, brown, violet or light gray – deep-water specimens are pale. They can grow up to 15 cm in moved shallow waters and up to 52 cm in deep sea. Spreading from a central disc with a ventral mouth and a dorsal anus it has 5 tapering arms with fore rows of tube feet each and blunt, upturned ends. The upper surface is covered in spines which are surrounded by pedicellariae, tiny pincers which keep detritus and other particulate matter from settling on the animal and discourage predators. The spines are outgrowths of exoskeletal plates called ossicles. The most apical tube feet of each arm are modified light sensory organs. The olfactory sense is good as well. Lost arms can be regenerated.
The tube feet are used for locomotion and capture of prey. This prey consists of mainly bivalves like mussels and oysters but also of roes, carrion, gastropods, crabs, polychaete worms and other echinoderms like sea urchins, starfishes, brittle stars and sea cucumbers. These are digesting by extruding the stomach which can intrude the slightly opened shell halves of a mussel.
The Common Starfish has separate sexes with a pair of gonads in each arm. From February to April, through ventral pores, females release about 2.5 million eggs each and stimulate the males chemically to release their sperm. Fertilization is external. The planctonic bipinnaria larva changes to a brachiolaria larva and settles after 21-87 days to metamorphose into a small starfish. The Common Starfish reaches maturity with one year but can live up to 5-10 years.
Did you know?
that the Common Starfish is used for homeopathic remedies and is a common souvenir? that starving Common Starfish can shrink? that French fishermen cut Common Starfishes apart to protect their oysters, but the starfish regenerated to two complete individuals and then affected the oysters even more?
|Name (Scientific)||Asterias rubens|
|Name (English)||Common Starfish|
|Name (French)||Etoile de mer commune|
|Name (German)||Gemeiner Seestern|
|Name (Spanish)||Estrella de mar común|
|Local names||Dutch: Gewone zeester
Norwegian: Vanlig korstroll
Portuguese: Estrela-do-mar comun
|CITES Status||Not listed|
|CMS Status||Not listed|
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|Range||Northern Atlantic Ocean from the White and Baltic Seas down to Cape Verde Islands and Senegal, also east off Canada|
|Habitat||In cold as well as tropical waters from the surface down to 650 m deep. Mainly on rocks and gravel where mussels and barnacle settle, less frequent on sediments like sand and mud and on algae carpets. Tolerates brackish water and sunshine.|
|Wild population||Most common starfish in north-eastern Atlantic Ocean. Sometimes they aggregate to 100 individuals or more on one square meter.|
|Zoo population||120 reported to ISIS (2008)|
In the Zoo
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Why do zoos keep this animal
The Common Starfish is long-lived, decorative and a suitable, common representative of echinoderms found around vast regions of the north eastern Atlantic Ocean. Its biomass is important to its ecosystem.