Crown-of-thorns starfish outbreaks have wreaked havoc on the Great Barrier Reef’s several reefs since 1962. In the World Heritage Area, a fourth outbreak is now ongoing.
Crown-of-thorns starfish (also known as COTS) are coral-eating marine invertebrates. They’re found on reefs all around the Indo-Pacific, and when the conditions are right, they may spread like a plague, decimating hard coral communities.
After coral bleaching, crown-of-thorns starfish are a major driver of coral loss on the Great Barrier Reef, according to our research.
On the Reef, AIMS manages a large crown-of-thorns starfish monitoring program. Over a 15-year period, this long-term study found that epidemics start in the north and travel south, with ocean currents moving larvae between reefs.
The surveys also reveal that good reefs rebound after outbreaks, but it takes 10 to 20 years. However, reefs that are subjected to additional stresses, such as coral bleaching, cyclones, or poor water quality, take longer to recover, and the coral may not fully recover before the next round of breakouts.
What do crown-of-thorns starfish look like?
The crown-of-thorns starfish (Acanthaster planci) has a central disk from which its arms emerge, similar to other starfish. They have many soft arms (more than the usual five) that are covered in spines, which distinguishes them from other creatures. Their arms are also prehensile, allowing them to grasp objects. Crown-of-thorns starfish can grow up to 10-14 in (25-35 cm) in length and have more than 20 limbs when fully grown. They’re also available in a range of colors, including bluish-purple, red, gray, and green.
How cute are they?
The COTS (a coral predator) is more interesting and appealing than cute. Their brilliant colors, such as purple, gray, and green, as well as their spiky body, are fascinating to observe.
How do they communicate?
The method these organisms communicate is mostly unknown. A recent study, however, may give some illumination, as it was discovered that they communicate with one another through chemical release. COTS from different places, such as COTS from the Indo-Pacific region (which are a coral reef pest) and COTS from Japan, have been found to release the same compounds. When they are attacked by a predator, they appear to emit various proteins, but there is still a lot more to discover about these fascinating aquatic critters.
How big is a crown-of-thorns starfish?
The average adult crown-of-thorns starfish is 10-14 inches long (25-35 cm). The long and pointed spines on the sides of the starfish’s arms and upper (aboral) surface resemble thistles, and can have up to 23 arms. They resemble a crown, which gives the animal its name. The spines are solid, pointed, and may easily puncture through fragile surfaces, growing up to 0.13 ft (4 cm) long.
How did it get its name?
The venomous thorn-like spines that cover the upper surface of the crown-of-thorns starfish (coral reef eater) give it its name. These resemble the biblical crown of thorns in appearance.
Would they make a good pet?
They cannot be kept as pets because they dwell in the waters and contribute to the balance of their ecosystems. Crown-of-thorns starfish are predators that eat a variety of corals. They can only live in the deepest parts of the ocean, where they may feed on vast amounts of corals.
Kidadl Recommendation: Only purchase pets from a reliable provider. It is important that you conduct your own research as a potential pet owner before deciding on your pet of choice. Being a pet owner is extremely rewarding, but it also necessitates a significant amount of time, effort, and money. Check to see if the pet you’ve chosen is legal in your state and/or nation. You must never capture wild animals or harm their habitat. Please double-check that the pet you’re thinking about buying isn’t an endangered species, isn’t on the CITES list, and hasn’t been captured in the wild for the pet trade.
Did you know…
One of the most interesting crown-of-thorns starfish facts for kids is that they feed on their prey, coral reef, by ejecting their stomachs from their bodies and covering the corals!
Crown-of-thorns starfish are nocturnal and can eat 53.8-140 square feet (5-13 square meters) of coral in a single year. COTS are the primary cause of reef damage in Australia’s Great Barrier Reef.
The poison of the crown-of-thorns starfish contains saponin, a chemical component that is deadly to both humans and fish. The sting of a crown-of-thorns starfish can produce numbness, tingling, nausea, and agony across the body.
On the Great Barrier Reef, AIMS has a large COTS checking operation. This long-term study found that epidemics start in the north and move south over 15 years, with the ocean transporting larvae between reefs.
Why is the crown-of-thorns starfish a problem?
Coral-eating crown-of-thorns starfish can be an issue. Under extreme circumstances, this sea star can have outbreaks that cause huge coral reef devastation, threatening the vital coral cover. Coral reefs are crucial for many undersea animals, and they also help to reduce the intensity of the waves that pound our coasts.
Can a crown-of-thorns starfish kill a human?
Although the venom of crown-of-thorns starfish (coral reef eater fish) cannot kill humans, their spines do contain neurotoxic and starfish poison, which is harmful to both humans and marine life.
We’ve painstakingly crafted a variety of interesting family-friendly animal facts for you to explore at Kidadl! Learn more about the ground beetle and the American dagger moth, two more arthropods.
You can even color one of our crown-of-thorns starfish coloring sheets at home to keep yourself occupied.
What is the biology of the crown-of-thorns starfish?
Crown-of-thorns starfish (Acanthaster planci) are a type of corallivore (i.e., they feed coral polyps) that can be found on coral reefs. They come in a variety of colors, ranging from purplish blue to reddish-gray to green, and are covered in sharp venomous spines. They usually have a diameter of 25-35 cm, although they can get as big as 80 cm.
Crown-of-thorns starfish can be found all over the Indo-Pacific region, from the Red Sea and East African coasts to the Pacific and Indian Oceans and Central America’s west coast. The gigantic triton snail (Charonia tritonis), stars and stripes pufferfish (Arothron hispidus), titan triggerfish (Balistoides viridescens), and humphead maori wrasse are all predators of COTS (Cheilinus undulates).
Crown-of-thorns starfish eat almost all corals, and their feeding preferences and behavior patterns change depending on population density, water motion, and species composition.
Is crown-of-thorns starfish good?
COTS are a vital part of the ecology on healthy coral reefs when present in large quantities. They devour the faster-growing corals, allowing the slower-growing species to catch up and increase the coral diversity of our reefs. The impact on coral reefs, however, can be fatal if the coral-eating starfish appears in large numbers.
Who eats crown-of-thorns starfish?
The gigantic triton snail, humphead Maori wrasse, starry puerfish, and titan trigger fish are all predators of adult crown-of-thorns starfish. Shrimp, crabs, and polychaete worms are all predators of immature starfish.
How is the crown-of-thorns starfish killing the Great Barrier Reef?
Thousands of crown-of-thorns starfish are thought to be eating their way through coral in a massive outbreak at the Great Barrier Reef’s southern end, while authorities contemplate how to deal with the problem.
The coral-killing marine animal’s outbreak on the Swain Reefs off Yeppoon was found last year, but the area is inaccessible and unfriendly, making management measures difficult.
Since last year, the Great Barrier Reef Marine Park Authority (GBRMPA) has been figuring out how to deal with the outbreak.
Fred Nucifora, the Authority’s director of education, stewardship, and partnerships, said monitoring workers visited the region last month to assess the matter.
“They performed some pre-emptive culling on the reefs while they were there in December,” Mr Nucifora said, adding that another operation is planned for January.
GBRMPA images and video show dozens of starfish covering large swaths of the reef.
Hugh Sweatman of the Australian Institute of Marine Sciences refused to give a figure, but stated the number of starfish counted was significant.
“We’re seeing very, very high densities, as high as we’ve seen in the past and as high as you’d expect to see,” Dr Sweatman said, “and there’ll surely be a lot of coral lost as a result.”
The starfish, which have toxic barbs that are dangerous to people, envelop the corals to consume them, according to him.
“Because the crown-of-thorns starfish has an extrudable stomach, it may lie on top of coral and wrap its stomach around it,” he explained.
“It doesn’t break chunks off the coral; instead, it digests the tissue off the skeleton… it’s highly effective at that.”
The starfish is a native of the reef, but when populations grow, the consequences can be disastrous, as thousands of the critters consume the coral.
“Each starfish eats around its body diameter per night, and it adds up quickly,” Dr Sweatman explained.
What is the biggest starfish in the world?
The sunflower star (Pycnopodia helianthoides) is the world’s largest starfish, having broken numerous records.
It has the widest arm spread of any sea star, extending around 40 inches from tip to tip, and can weigh up to 11 pounds. It also possesses the most arms of any animal that science has discovered.
Aside from its size, the amount of limbs on this sea star is what makes it so amazing. Adults have more symmetrically arranged arms than any other known species, with up to 24.
They resemble sunflowers because some of the individuals are a rich yellow color, with all of the arms resembling petals. Sunflower stars occur in a variety of colors, including purple, orange, red, and brown, in addition to yellow.
They have thousands of yellow or orange tube feet beneath them, making them paler. These feet operate as suction cups, giving the sea stars a firm grip and assisting them in grabbing and opening their prey, which includes mollusks, sea urchins, and crabs.
The feet are also used for walking, and this species can travel at a surprising velocity of up to 40 inches per minute, according to the Monterey Bay Aquarium.
What does the Bible say about the crown of thorns?
During the circumstances leading up to Jesus’ crucifixion, a woven crown of thorns was placed on his head, according to the New Testament. It was one of the Passion’s instruments, used by Jesus’ captors to both inflict suffering and mock his claim to authority. It is mentioned in the gospels of Matthew (“And when they plaited a crown of thorns, they put it on his head, and a reed in his right hand: and they bowed the knee and mocked him, saying Hail, King of the Jews!” 27:29), Mark (15:17), and John (19:2, 5) and is frequently alluded to by early Church Fathers such as Clement of Alexandria, Origen, and others.
What was the crown-of-thorns made of?
They were moved to Notre Dame in 1806, where they were worshipped by the entire city of Paris.
Every Good Friday at a special liturgy at Notre Dame, the crown of thorns, now preserved in a gilded and crystalline reliquary, is brought out for the devout.
A twisted wreath of rushes from Juncus balticus, a perpetually flowering rush native to northern Britain, the Baltic, and Scandinavia, forms the crown.
The Ziziphus spina-christi plant provides the thorns seen in numerous reliquaries, notably the rooster that guarded Notre Dame’s pinnacle until the fire broke out.
The oldest known Ziziphus is said to be 2000 years old and grows near Ein Hatzeva, Israel, south of Jerusalem.
What happened to the crown-of-thorns?
The thornless remnants are housed in the treasury of Notre-Dame Cathedral in Paris, where they survived a horrific fire that devastated the roof and spire of the church in April 2019.