The Incredible, Yet Harmful Crown-of-Thorns Sea Star

Crown of thorns starfish (Acanthaster planci), courtesy of NOAA Photo Library

Although I have always loved everything about the sea since I could remember, I have been fascinated most with the phylum Echinodermata since highschool, specifically classes Asteroidea (sea stars) and Holothuroidea (sea cucumbers). I’ve often asked myself what it is about these creatures that so thoroughly intrigues me and frankly, I think it’s due to how little I used to know about them. Growing up, I had the impression that sea stars were naturally hard and unavoidably stationary. I was surprised to find out otherwise.

These past years watching “Deep-Sea Live” from the Okeanos Explorer, a NOAA research vessel, I have been enlightened in so many ways. I am always happy to see species from one of these classes and I wouldn’t be surprised if the bulk of the screenshots I’ve taken on this computer consist of these subjects. During the last (and just concluded) expedition in Hawaii, I was often amused at the continual ‘bickering’ between two of the scientists whenever we would observe a sea star enjoying a meal of coral. Of course, the sea star has to eat, right?

I have recently realized that some of these cute little, often pentamorous, creatures can have a devastating effect on coral populations. It’s a dog eat dog world, they say, and it’s no surprise when something you find adorable has a dark side to it. It makes me wonder what life would be like now if not for the curse?

The Crown-of-Thorns starfish (COTS) is a good example. I first came upon the prickly creature while researching for a paper. I was enamored. I saw groups of them feeding on coral aggregations, a man skillfully holding one from underneath, and the effects of being pricked by one of the creatures spines. They are one of my favorite marine creatures to read about today. But it might surprise you how much harm an outbreak can cause.

Courtesy of NOAA Photo Library

In a well-balanced ecosystem COTS works with the coral to keep it from overpopulating. This is none other than a skillfully planned case of superior design. Unfortunately, as with so many other things, the curse of sin brought on by man in the beginning has wreaked havoc on God’s perfectly balanced creation. COTS population has blown out of proportion and in some locations have destroyed over 90% of coral life. Resulting in the need for serious action. Scientists have spent as much as $3 million in poison in an effort to save the reefs. But the battle rages on. Recently, they have found “store bought” vinegar can do the job with less financial cost.

My first question was: why? What causes COTS outbreaks? My suspicions proved true when I read from multiple sources that a high cause is due to agricultural runoff. More specifically, nitrogen pollution. Simply put, the nitrogen causes an increase in plankton, on which COTS larvae dine, and the result is a dangerous increase in COTS population. It is all too common to find out the root of a problem lies with man mishandling creation. Other causes are lack of predators, and there is thought that El NiƱo plays a part as well.

All actions have consequences, even ones as seemingly unimportant as over fertilizing. God put us in charge of this planet as stewards to take care of it. Cutting down more trees than is necessary, killing off entire species, and dumping trash in the ocean is hardly fulfilling that responsibility.

What a world it would be if nature was perfectly balanced like it was before the fall of man. And yet, despite the destructive ramifications, God still keeps a balance to nature.

“Who shut in the sea with doors, when it burst forth and issued from the womb; when I made the clouds its garment, and thick darkness its swaddling band; when I fixed My limit for it, and set bars and doors; when I said, ‘This far you may come, but no further, and here your proud waves must stop!'” *

“You alone are the Lord; You have made heaven, the heaven of heavens, with all their host, the earth and everything on it, the seas and all that is in them, and You preserve them all.” **

I’ve been struck by these two verses many times. Just like God’s promise to never again send a global flood, He is trustworthy and dependable. He will sustain us. 

Now what will we do?

*Job 38:8-11 (NKJV)
**Nehemiah 9:6 (NKJV)
References and further reading:
-“Divers kill crown-of-throns starfish with vinegar”, SCUBA News,
-“Great Barrier Reef dying beneath its crown of thorns”, The Conversation,
-“High-tech fertilisers and innovation have come to the Great Barrier Reef’s escue”, The Conversation,

Share this

Leave a Reply

Your email address will not be published. Required fields are marked *