Crown of thorn Sea Star
Tagged: animal, animals, fishCrown of thorns Sea Star
The Crown of Thorn sea star is found on coral reefs in the Indian and Pacific Oceans. It occurs in its greatest numbers on the Great Barrier Reef in Australia and around the islands of Indonesia. Many armed and covered in long, poisonous spines, the crown of thorns sea star has a forbidding appearance and reputation as one of the most destructive marine animals. These starfish feed voraciously on the living corals that make up tropical reefs. Congregating sometimes in tens of thousands, they move like a slowly advancing army over a reef, leaving behind a wasteland of destroyed coral that will take many years to recover.
Controlling Interest
Conservationists are looking for ways of controlling the crown of thorns sea star. Million have been culled, but to limited effect. Erecting underwater fences around small areas of reef works well in keeping out the adult sea stars, but such a project is unlikely to be practicable on a large scale and would not keep out the animals larvae. One possibility is the use of biological control methods, such as the introduction of predators, but this risks disturbing an area,s ecological balance.
Part of Bodies
- Skin is reinforced with tough particles made up of magnesium calcite
- Number of arms varies-may be as many as 23
- Poisonous spines, up to 3 cm long, break off and lodge in the skin if the animal is handled
- Central disc contains the stomach, digestive organs and sex organs. The anus is placed at the top of the body
Statistics
- status – locally common
- diameter – up to 40cm
- sexual maturity – 2 years
- breeding season – summer months
- number of eggs – up to 60 million in season
- diet – corals; also algae and crustaceans
- lifespan – up to 7 years
Myth of fact
Lots of people think that sea stars have eyes. What they actually have are eyespots at the tip of each arm which act as light sensors. These sensors contain a red pigment which changes when light is present and may enable the sea star to get its bearings.
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