“…and today we’re talking about a starfish that the jester stole. But more on that later.”
Dive into the dazzling depths of the ocean, where a spiky sovereign slinks silently across coral castles, whispering secrets through an invisible ink of proteins. This prickly predator, a veritable porcupine of the sea, rules the reefs with a chemical charisma that’d make even the most stoic fish blush. Its vibrant veneer hides a cunning communicator, passing messages like a marine Morse code master, all while wreaking havoc on coral communities. Prepare to be pricked by curiosity, like the Crown of Thorns Starfish here in Life, Death, and Taxonomy.
Description of the Crown of Thorns Starfish
COTS has a distinctive, disc-shaped body with 10–21 radiating arms covered in sharp, venomous spines that resemble thorns, hence its name.
Varies from reddish and purple to green or gray, often with bright warning colors to deter predators.
Measure Up
Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com.
Diameter of the Crown of Thorns Starfish
Adults typically range from 25 to 35 cm in diameter, though some can grow up to 80 cm.
The Crown of Thorns Starfish has a diameter of 35 cm (13.78 inches). How many objects fit into the starfish’s diameter (if the object is shorter) or how many starfish fit into the object’s length/diameter (if the object is longer)?
a) The diameter of a giant barrel sponge
A giant barrel sponge (Xestospongia muta), common on Indo-Pacific reefs, has a diameter of about 1 meter (100 cm or 39.37 inches) for a large specimen, per marine biology data.
b) The length of a Filipino bangkung blade
The blade of a bangkung, a traditional Filipino short sword used by coastal communities, measures about 25 cm (0.25 meters or 9.84 inches), based on ethnographic records.
c) The length of a clownfish
A clownfish (Amphiprioninae), iconic to Indo-Pacific reefs like Australia’s Great Barrier Reef, measures about 12 cm (0.12 meters or 4.72 inches) in body length for a large adult.
Question: How many fit into each diameter comparison?
A) 2.9 Crown of Thorns Starfish go into the diameter of a giant barrel sponge
B) 2.4 Filipino bangkung blades go into the diameter of a Crown of Thorns Starfish
C) 3.9 clownfish go into the diameter of a Crown of Thorns Starfish
Weight of the Crown of Thorns Starfish
The Crown of Thorns Starfish weighs 18 ounces (510 grams). How many objects fit into the starfish’s weight (if the object is lighter) or how many starfish fit into the object’s weight (if the object is heavier)?
a) The weight of an Indonesian coral necklace
A traditional Indonesian coral necklace, crafted from reef materials in Bali, weighs about 100 grams (0.1 kg or 3.53 ounces), per cultural artifact data.
b) The weight of a sea cucumber
A sea cucumber (Holothuria scabra), found on Indo-Pacific reefs, weighs about 300 grams (0.3 kg or 10.58 ounces) for an average adult, per marine biology data.
c) The weight of an Aboriginal woomera
A woomera, a wooden spear-thrower used by Aboriginal Australians near coastal reefs, weighs about 800 grams (0.8 kg or 28.22 ounces) for a standard piece, per ethnographic records.
Question: How many fit into each weight comparison?
A) 5.1 Indonesian coral necklaces go into the weight of a Crown of Thorns Starfish
B) 2.7 sea cucumbers go into the weight of a Crown of Thorns Starfish
C) 3.6 Crown of Thorns Starfish go into the weight of an Aboriginal woomera
Fast Facts
Found across the Indo-Pacific, from the Red Sea and East Africa to the Pacific Islands, including Australia, Southeast Asia, and parts of the Indian Ocean.
Habitat: Prefers coral reef environments, particularly shallow waters (0–30 meters) where coral is abundant, though it can live at depths up to 200 meters.
Ecology: Thrives in warm waters with high coral cover, often hiding in crevices during the day and feeding at night.
Diet: COTS is a corallivore, primarily feeding on the soft tissue (polyps) of hard corals, such as branching and table corals (e.g., Acropora species).
Feeding Mechanism: It extrudes its stomach over coral to digest the polyps externally, leaving behind a white, dead coral skeleton. A single COTS can consume up to 6 square meters of coral per year.
Impact: During population outbreaks, COTS can devastate reefs, reducing coral cover significantly and disrupting reef ecosystems.
Reproduction: COTS are broadcast spawners, releasing eggs and sperm into the water column. A single female can produce 60–100 million eggs per spawning season.
Spawning Season: Typically occurs in summer months (e.g., December–February in the Southern Hemisphere) when water temperatures are warm (around 26–28°C).
Larval Stage: Eggs develop into planktonic larvae, which drift for 10–30 days before settling on reefs and metamorphosing into juvenile starfish.
Growth: Juveniles grow rapidly, reaching maturity in about 2 years. Adults can live up to 8 years.
Major Fact: You Need to Get More Protein in your Coral Diet
- The Crown of Thorns Starfish uses proteins to communicate, releasing chemical signals into the water to coordinate behaviors like spawning or feeding frenzies.
- These proteins act like molecular memos, triggering nearby starfish to synchronize their reproductive cycles, ensuring a mass spawning event.
- Chemical signaling helps them locate each other in the vast ocean, like sending a text in a group chat to rally your motorcycle gang.
- The proteins can signal distress or attract others to food sources, turning a single starfish’s coral buffet into a full-blown feast.
- This communication method solves the problem of coordinating across large distances in murky or turbulent waters where visual cues fail.
- By releasing specific proteins, they can influence the behavior of other marine organisms, sometimes repelling predators or competitors.
- The impact of this protein-based communication can amplify their destructive feeding on coral reefs, as synchronized groups devour larger areas.
- These chemical cues are highly specific, ensuring only Crown of Thorns Starfish respond.
- Environmental factors like water temperature and currents can affect how far and fast these protein signals travel, influencing their effectiveness.
- Overuse of this chemical chatter can lead to overpopulation in certain areas, exacerbating their reputation as coral reef devastators.
Ending
So surf the reefs, eat some coral, and use protein signals to coordinate all your gym bros to converge on a feast like the Crown of Thorns Starfish here in LDT.