It has been 7 months since I was stationed on Rawa Island in Johor. Living on an island has always been my dream. Growing up in Kuala Lumpur, a city crowded with cars, made me sick of the traffic jams and fast pace of lifestyle. Now, my dream came true! Thanks to Orca Scuba and Rawa Island Resort for making this happen!
My office for the past 7 months
But hey, I am not here for a vacation. Let’s move on to the working part – Project SURI.
The ‘Sea Urchin Rawa Investigation’ (Project SURI) is a project run by Team Sea Habitats from the University of Malaya, in collaboration with Rawa Island Resort and Orca Scuba. Under this project, observational studies and experimental studies are conducted on-site to understand the ecology of the sea urchin such as its population distribution, its role in the marine ecosystem, and its behaviour. This project is closely related to my Master’s thesis at the University of Malaya, titled “The distribution and movement patterns of sea urchins in tropical habitats”.
Urchins commonly found on Rawa’s reef. (left) Echinothrix calamaris; (right) Diadema satosum.
Tagging the sea urchins
To study the movement patterns of sea urchins, I am using the “Tag and Track” method, which involves attaching a fishing hook and a wooden cork as a marker to the urchins. To tag the urchins was easier than I thought. Imagine the sea urchin as a big ball of needles, handle it like how you handle the needle: gentle and slow. No need to be afraid of them because they don’t really poke or shoot you with spines, unless you are the one who starts the fight.
(left) A tagged Diadema setosum; (right) Diver tagging the sea urchin.
In the daytime, sea urchins don’t usually move much. But after I tagged them, they feel threatened and seek protection, as they start to move toward coral crevices or to hide underneath rocks. I go back into the water every 4 hours to record their positions, until the 24-hours cycle is completed. For now, the first set of 24-hours movement patterns study has been completed. I am still in the middle of analysing data from that tagging event, but here are some interesting observations I would like to share with you guys.
Threatened urchin seeks comfort from friends?
During my tagging practice, I noticed that tagged urchins tended to move closer to another urchin if there was no shelter available for them. When they get in touch with each other, their spines will move faster than normal, like they are communicating! Are they trying to warn the others? Or are they seeking for help? Sea urchins, like all Echinoderms, have no brain, hence it will be interesting to find out how they convey and receive messages.
Sea urchins have different personalities?
Within the 24-hours, there were urchins that travelled up to 30 meters, but there were also those that stayed in the same spot, not moving at all. Since all tagged urchins were in the same area, I assumed they receive the same predation and foraging pressures, which did not provide an explanation for their different behaviour. Could different sea urchins have different personalities? Maybe, some of them are the adventurous type that like to explore their surroundings, while others just prefer to stay in the shelter to be safe.
Exhausted divers after the 24-hour survey.
There are so many unsolved questions about this mysterious creature. With this project, I hope we can understand more about the urchin because science is gradually revealing them to play a role in maintaining the stability of marine ecosystems and in boosting coral reef resilience. Who knows, this underappreciated creature could be a hidden gem, and its potential to protect and rescue our reefs is waiting to be unleashed!
Mok Man Ying
Team Sea Habitats