cockroaches of the sea

katie bimson

Even the name sounds intimidating: the crown of thorns starfish (COTS). This starfish is currently one of the most prolific coral predators due to recent outbreaks around the world. A single COTS can consume 5-6m2 of coral per year. They have few natural predators, and one individual can produce over 60 million eggs in a year. Did I mention that they are covered in venomous spines, and envenomation causes severe pain, swelling, and can send a victim to the hospital? So naturally, after arriving at the paradise oasis that is Anantara Dhigu, my colleague M and I were jolted out of our reverie when we set out with the Coral Reef CPR team to collect as many of these creatures as we could find.



Andy described the procedure to us: one person holds the “goody bag” and the other uses the PVC pipe to scoop up the COTS and bring it to the bag, where the holder will assist in stuffing it into the mesh. Easy, right? Except for the fact that these creatures have between 7-23 arms, all covered with tiny tube feet to latch them on to the bottom, meaning they must be pried from the substrate. They also prefer hiding in and under corals, further complicating their removal. Andy and Georgia both made it clear that contact with these animals was not to be taken lightly, and provided various personal horror stories to support their warnings: hospital trips, COTS induced hallucinations, and swollen feet too large to fit in shoes. Never having done this before, I was more than a little nervous about these creatures, and on our first dive, I wasn’t much help to M, who had prior experience and clearly a lot more chutzpah than I. He took control and set off collecting them, while I merely pointed out the starfish I found. In total, our team found 9 individuals, more than should be present, but not a severe outbreak.

            After one dive of learning how it was done from the professionals, I was ready to get involved. The next day we set out on Stage reef, an area that we were warned had a high density of COTS. We were to follow the same procedure as the last dive, working in pairs and making our way along the reef, and this time, I was determined to capture my own COTS. I started the dive holding the bag for M, while he used his skills to dislodge the starfish and place them into the bag. A seemingly easy task, however, I was constantly aware that I was holding a swinging bag full of venomous creatures, which could seriously injure me if I wasn’t careful. After watching M’s method, I gathered up my nerves and began prying off my very own COTS. After successfully dislodging it, the trick is to bounce it on the pipe to get it near the bag opening and then guide it inside. Fortunately, after years of playing field hockey and bouncing the ball on the stick in the air, my hand eye coordination is quite good, and all external factors aside (being underwater, bouncing a ball of venomous spines, strong current swaying both diver and COTS side to side) I managed to gracefully score a point, placing the organism into the goody bag.


As it turns out, once you’ve collected about 15 of these creatures, you really get the hang of it, and almost start to enjoy it in a strange way. Knowing that each removal leads to higher coral survival provides a great incentive as well. Upon our arrival at the dock, we put the 50 or so COTS in the trash to dispose of them, but not before collecting some tube feet samples so that Georgia and Andy can get more information on their origins and genetics. They are incredibly resilient creatures, and can survive if placed back into the water after a few days, therefore the trash is the best disposal method. As Georgia said to me over breakfast: “If there was an apocalypse, cockroaches and COTS would be the only survivors!”