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.
Why is the crown-of-thorns starfish a big problem for the reef?
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.
Why crown-of-thorns starfish is considered as harmful pest to human?
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.
Is the crown-of-thorns starfish an invasive species?
- Purple sea urchins (Strongylocentortus purpuratus) are native to the United States’ Pacific Coast. Natural predators of the purple sea urchin, such as sea otters and sea stars, have declined in numbers (Pearse 2006). The resulting population explosion of purple sea urchins has ravaged kelp forests, which are important homes for many marine animals (Pearse 2006).
- Europe and North Africa are home to the European Green Crab (Carcinus maenas). The crab, which is found in the Americas, Australia, and South Africa, preys on a wide range of creatures but is especially damaging to bivalves (Colnar & Landis 2007).
What is being done about the crown-of-thorns starfish?
As part of the Marine Park Authority’s Crown-of-thorns Starfish Strategic Management Framework, the Crown-of-thorns Starfish Control Program was formed in 2012 and provides a tactical reaction to outbreaks.
The method employs dedicated vessels with highly trained crews to hand cull starfish using bile salts or household vinegar as a deadly injection. The Crown-of-thorns Starfish Control Program also includes strategic surveillance and monitoring efforts. This ensures that culling efforts are focused on the areas that will provide the most benefit, that progress is tracked, and that pest control outcomes are maintained once they have been reached.
Supporting the environment and Reef communities
The Crown-of-thorns Starfish Control Program provides social and economic benefits to Australians in addition to environmental benefits for the Great Barrier Reef’s health. The program has been delivered in collaboration with the Reef tourism industry through the Association of Marine Park Tourism Operators since its inception (AMPTO). The reef is kept healthy in areas where local tourism firms send their national and international customers to experience the Great Barrier Reef through targeted crown-of-thorns starfish control. More than 100 people, mostly from Queensland, are trained and employed as part of the initiative.
Program growth and funding
At first, the program only had one or two dedicated ships. However, the outbreak that started in the northern management region in 2010 migrated south over time. The Crown-of-thorns Starfish Control Program received more money in 2018. In 2018-19, the program was able to expand from two to six vessels thanks to the additional funding. The expansion of the program allowed for the first time the deployment of crown-of-thorns starfish control vessels in the Marine Park’s far north and far south.
Five crown-of-thorns starfish control vessels have been deployed in the Marine Park’s northern, central, and southern management districts as of 2019-20. Control activities are deliberately tailored within each management region to focus on reefs of high ecological and economic value.
Since 2012, the Australian government has been funding the Crown-of-thorns Starfish Control Program. The Reef Trust Partnership (RTP) between the Great Barrier Reef Foundation (GBRF) and the Department of Agriculture, Water and the Environment provided funding for the Program in 2019-20. (DAWE). The GBRF and the DAWE have fully supported it through the RTP for 2020-22. The GBRF, the Great Barrier Reef Marine Park Authority (the Marine Park Authority), and the Reef and Rainforest Research Centre have formed a strategic collaboration to deliver the Program’s manual in-water control component (RRRC).
What is the crown-of-thorns Great Barrier Reef?
Along with climate change, bleaching, illegal fishing, and water quality, Crown of Thorns Starfish are one of the most serious threats to the Great Barrier Reef. Since 1985, the Crown of Thorns starfish has been responsible for 40% of the Great Barrier Reef’s coral cover loss.
Crown of Thorns are native to the Great Barrier Reef and are not invasive or introduced. However, if the animals reach epidemic proportions, they have the ability to drastically alter the structure and biological diversity of the reef environment. The creatures are corallivores, which means they eat mostly live coral tissue.
Healthy coral isn’t the only component of a healthy reef.
Healthy coral supports a diverse range of marine creatures, all of which work together to keep the reef ecosystem healthy and thriving.
Although Crown of Thorns are found naturally on the Great Barrier Reef, human involvement with the natural system and processes has caused issues in recent decades, allowing populations to reach epidemic proportions.
The absence of their natural predators owing to overfishing, as well as increased nutrient loads from a land-based run-off and bad land management techniques, have been the major challenges in recent years for crown of thorns starfish.
A single person can produce up to 65,000,000 babies, and their offspring thrive on the ecosystem’s abundant nutrients. Because of this, combined with the lack of natural predators, Crown of Thorns starfish populations have been able to expand to extremely large numbers, making control difficult in some locations.
The positive news is that the Great Barrier Reef Marine Park is one of the best maintained protected ecosystems in the world and there is a great deal of study, science and management being conducted to better understand and contain this reef issue. Fortunately, Lady Musgrave is far enough from the mainland to avoid any runoff-related water quality issues, and the fact that we operate within a protected “no-take” green zone protects the area from overfishing.
Lady Musgrave Experience keeps a close eye on the reef for possible Crown of Thorns outbreaks. We like including our visitors in this vital monitoring and conservation effort. In the past, our citizen science programs have detected when the crown of thorns population has risen over natural levels. We can control and eliminate dangers with early intervention and a proactive and quick response by reporting this information immediately to the marine park management authority. Sign up for our Marine Biologist for a Day program to learn more about Crown of Thorns Starfish and get engaged in monitoring and control.
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.
What is the effect of the presence of many Crown of Thorns sea star to the ecosystem and its biotic components?
The crown-of-thorns starfish cause a succession on reefs by injuring corals, increasing the diversity of coral species and biological niches on the reef.
Why are starfish killing the Great Barrier Reef?
The Great Barrier Reef, which stretches almost 865 million acres off the coast of Australia, is home to 350 billion starfish. Overfishing and the extinction of the starfish’s natural predators, such as the gigantic triton snail, have aided 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 vibrant colors, such as purple, gray, and green, as well as their spiny 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. A crown-of-thorns starfish sting can produce numbness, tingling, nausea, and bodily discomfort.
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 starfish is killing the Great Barrier Reef?
New study is assisting in the prevention of crown-of-thorn starfish outbreaks, which are a huge danger to the Great Barrier Reef. Coral reefs are under jeopardy. Climate change is having an effect, and ravenous crown-of-thorns starfish (COTS) are a persistent problem.