Deep Dive: The Angry Starfish Killing Our Coral

Words and art by Freya Lauersen

When I was 13 years old, my best friend Sarah and I experienced what we shall eternally call “that haunted day”.

Like any other Australian teen determined to become closer to the likes of Blue Water High, we decidedly set out along the Mornington Peninsula to the nearest supermarket for some lemons, with which we would bleach our hair to beachy-blonde perfection. Before wading our way through the coastline, I found a colourful, conveniently backpack-sized starfish washed ashore. 

Almost a decade later I find myself taking any free time to visit Sarah, now living up in Townsville, working to restore the fragile beauty of the Great Barrier Reef… from coral-nibbling starfish! A huge twist of events.

The Crown of Thorns Starfish (COTS), according to scientists, are single-handedly responsible for almost 40% of the coral reef’s loss. And unlike the dazzling creature I once found, these underwater villains are as ugly as they are traitorous. 

Sarah: I think they’re ugly-cute. 

Me: Nothing with that amount of legs is cute. So, can you tell us a bit about how you got here?

Sarah: Well, I was a year into starting my bio-med degree and I felt like I had the choice of going down one path or taking the chance to do something completely different. I had no interest in becoming a GP and I felt like there was still a lot to learn about the world and myself.

Me: South America seems like a good place to figure things out. 

Sarah: Yeah, I mean I’m still working things out! But I started travelling there for six months and sort of fell into scuba diving, along the thrilling ‘gringo trail’. A lot of my friends think I got here because of a—clearly valuable—under-water acid trip I had there.

After I came back, I did an internship in Byron Bay where I got my dive masters qualification in a matter of months. I liked the adventurous sound to the job and I could imagine myself in that field. Then I travelled further north and decided to study marine science at James Cook University (JCU). 

Me: Is that where you discovered the job of working on the reef?

Sarah: No, I discovered the COTS job by complete luck. I was quite interested in spearfishing at the time. Not only does it get you involved with water but it is also a very sustainable way of fishing.

I went to this spearfishing club night at some dingy RSL pub in Townsville. I got talking to this guy, very casually, who said I should apply for this job on the water disarming COTS. I applied that night and later found out that I had been speaking to the CEO of the whole company, which was pretty crazy. 

Me: So, what is a regular workday like for you?


6am: Breakfast. Originally, we had an unlimited supply of avocados and coconut water but the boss cut them off the shopping list.

7am: Manta tow. Someone gets towed by the boat on this board that glides under the water and counts how many starfish they can see. That way we can prioritise highly infected zones.

8am: Get scuba gear and needle guns ready and split into two groups.  

8:30am: Two sets of hour-long dives. Killing up to 100 COTS at a time.

12pm: Lunch. Each crew member has one day off cooking for the boat. 

1pm: Two more dives. 

4pm: Chill out. Play cards. All week you’re surrounded by only flat water, the sunset is surreal. 

6pm: Dinner. Because you’re in the water for such long lengths of time, your skin becomes so soft and your body becomes this sort of battleground of injuries. We’d all sit around this tiny TV, each with our own scratches and bruises, to watch this show about pirates called Black Sails, and I liked to think the life we were living was like a pirate. 

Me: Blimey. So, what kind of challenges do you face in tackling these critters?

Sarah: Zombie starfish. If you don’t stab them properly, you see them walking around with half their body deflated. It’s both impressive and frightening how they regenerate.

Me: I read that they can last 6-9 months without food.

Sarah: Well, in a balanced ecosystem, the COTS are actually an integral part in keeping the reef diverse. They feed on this fast-growing coral called Acropora which then gives other coral a chance to grow. But now their population is unsustainably high and the reef isn’t growing fast enough to support it. 

Me: Why are we seeing more of them? 

Sarah: Mainly poor water quality. Agricultural run-off creates more nutrients for plankton to thrive, which the COTS larvae feed off, making their survival rate super successful. And their natural predators, giant triton snails, are getting overfished. Their shell is really pretty and many people try to collect or sell them. 

Who would have thought that “the haunted day” would have scarred one of us for life and inspired the other for the future? 

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