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Crown-of-Thorns Sea Star

Acanthaster planci

The crown-of-thorns sea star has a unique appearance due to its venomous spikes and spines. The stars prey on coral, scurrying over the reefs, and eat the soft polyps inside. While not normally a threat to reefs around the world, population outbreaks can occur due to anthropogenic (human caused) influences such as overfishing of their predators or nutrient runoffs that cause plankton blooms which are eaten by the sea star larvae.

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SPECIES IN DETAIL

Crown-of-Thorns Sea Star

Acanthaster planci

CONSERVATION STATUS: Invasive Species

CLIMATE CHANGE: Uncertain

Geographic Distribution

The crown-of-thorns star lives in the tropical Pacific, Indo-Pacific, and Indian Oceans.

Habitat

Crown-of-thorns sea stars can be found on coral reefs in the tropical regions of the Pacific, Indo-Pacific, and Indian Oceans. Their average depths range from 6—12 meters (19—39 feet).

Physical Characteristics

Crown-of-thorns sea stars are large sea stars with a wide disc-shaped body and many arms covered in sharp spines. They can have up to twenty-one arms! They range in color from purple and reds to green, grays, and browns depending on their region. Their arms are flexible and can curl which allows them to move quickly over reefs.

Size

Average Size: 25 to 35 centimeters (10 to 14 inches) in diameter.

Diet

Crown-of-thorns sea stars are tremendous coral eaters. Depending on location, they will eat different species of coral. As they scurry over the reefs, they feed by inverting their stomachs out of their mouths and digest the polyps from within the coral. An adult crown-of- thorns sea star can consume up to 10 square meters (108 square feet) of coral a year.

Reproduction

Crown-of-thorns sea stars reproduce by spawning, an act of releasing sperm and eggs into the water. After climbing to a high surface on a reef, a sea star arches its body and releases a special chemical to induce spawning in nearby individuals. Once fertilized, the larvae float until they are ready to settle onto a hard surface and begin transforming into a juvenile sea star.

Behavior

The crown-of-thorns sea star migrates over great distances. It can move as quickly as 35 centimeters (13 inches) a minute and eat its prey as it moves!

Adaptation

The crown-of-thorns sea star is covered in venomous spines to protect itself from predators. Its flexible arms help it travel quickly over reefs in search of coral to eat.

Longevity

The average lifespan of the crown-of-thorns sea stars in the wild is approximately 5—7.5 years, yet they may live anywhere from 7—15 years under human care.

Conservation

Crown-of-thorns sea stars do not seem to be impacted negatively by climate change. The warmer water temperatures prompt conditions which increase spawning events and population outbreaks of these sea stars on coral reefs, causing substantial damage to the reefs.

SPECIES IN DETAIL | Print full entry

Crown-of-Thorns Sea Star

Acanthaster planci

CONSERVATION STATUS: Invasive Species

CLIMATE CHANGE: Uncertain

The crown-of-thorns star lives in the tropical Pacific, Indo-Pacific, and Indian Oceans.

Crown-of-thorns sea stars can be found on coral reefs in the tropical regions of the Pacific, Indo-Pacific, and Indian Oceans. Their average depths range from 6—12 meters (19—39 feet).

Crown-of-thorns sea stars are large sea stars with a wide disc-shaped body and many arms covered in sharp spines. They can have up to twenty-one arms! They range in color from purple and reds to green, grays, and browns depending on their region. Their arms are flexible and can curl which allows them to move quickly over reefs.

Average Size: 25 to 35 centimeters (10 to 14 inches) in diameter.

Crown-of-thorns sea stars are tremendous coral eaters. Depending on location, they will eat different species of coral. As they scurry over the reefs, they feed by inverting their stomachs out of their mouths and digest the polyps from within the coral. An adult crown-of- thorns sea star can consume up to 10 square meters (108 square feet) of coral a year.

Crown-of-thorns sea stars reproduce by spawning, an act of releasing sperm and eggs into the water. After climbing to a high surface on a reef, a sea star arches its body and releases a special chemical to induce spawning in nearby individuals. Once fertilized, the larvae float until they are ready to settle onto a hard surface and begin transforming into a juvenile sea star.

The crown-of-thorns sea star migrates over great distances. It can move as quickly as 35 centimeters (13 inches) a minute and eat its prey as it moves!

The crown-of-thorns sea star is covered in venomous spines to protect itself from predators. Its flexible arms help it travel quickly over reefs in search of coral to eat.

The average lifespan of the crown-of-thorns sea stars in the wild is approximately 5—7.5 years, yet they may live anywhere from 7—15 years under human care.

Crown-of-thorns sea stars do not seem to be impacted negatively by climate change. The warmer water temperatures prompt conditions which increase spawning events and population outbreaks of these sea stars on coral reefs, causing substantial damage to the reefs.