Coral Relocation at Sultan Shoal

Date April 26, 2014

The Hantu Blog visited the reefs of Sultan Shoal this morning to participate in coral relocation efforts initiated by the Maritime and Port Authority (MPA), and led by scientists from the Danish Hydrology Institute (DHI).

It’s the first time we are diving Sultan Shoal, and harvesting live coral. While participating in the Comprehensive Mega Marine Survey, we collected coral rubble, but extra care has to be taken when harvesting live coral as we want to minimise the impact and stress on these corals, so that they have a better chance at surviving the relocation process.

The first thing that struck me as we descended onto the shallow reefs at Sultan Shoal, were the number of tinsy tiny sea cucumbers that filled in all the gaps between the corals!

There were millions of them! I’ve never seen anything like that on other reefs around Singapore, and after speaking to scientists with DHI, they too said that this these tiny sea cucumbers occurring in such sheer numbers seems to only occur at Sultan Shoal.

While lobbing off the coral heads, this bizarre-looking clam dropped out from the underside of the coral. I shared this photo with Eugene Goh from DHI and he said that they have often encountered these clams when harvesting corals as they seem to like to wedge themselves in the crevices between coral. That might explain why we haven’t seen them while diving along the reef slopes. Could it be a File clam (Lima lima)?

Here’s a video of it just before I dropped it back into some cracks amongst the rocks. Hopefully it’ll find safety there.

Volunteers were given very precise instructions on what genera of coral to collect. For this harvest, we collected lots of Fungia, simply because they are so easy to collect! But we also harvested lots of boulder and foliose coral. It does take some careful placement of the chisel to get the coral heads off nice and smooth! Before the trip, we were shown a video demonstration on how to remove coral heads, and then a live demonstration in the water today, before we headed off to find and harvest our own corals. While we were at work, scientists swam around to supervise us and made sure that we were all doing it right, with minimal damage to the corals.

There was a section of the reef that was simply smothered by anemones and anemonefish! Hovering above the anemones, one can watch as a single fish swims amongst the tentacles of as many as six different individual anemones! I found that really interesting, and wondered if that individual fish guards all those anemones against other anemonefish, or if the anemones are somewhat communal. Some fish would even leave their anemone, swim over a bunch of anemones in midwater, and descend into another anemone further down the reef.

While doing our safety stop I came across a yellow-version of those tiny sea cucumbers. There were tonnes of them tucked into the base of the coral heads we had harvested. They were EVERYWHERE!

Some razorfish drifted by.

After we loaded the corals onto the boat and doused them with sea water to try to keep them moist and comfy, out popped this little octopus from the basket! It crawled around the deck of our boat before it was spotted. Good thing no one stepped on it! It was promptly picked up and tossed back into the water.

Our corals then went to meet the press on Sultan Shoal island. Eugene Goh from DHI shares a little about the different types of coral that can be found in our waters, with MPA Chief Executive, Andrew Tan, as many journalists listened in.

Journalists were allowed to briefly handle the coral, and it was a unique opportunity land dwellers to get real close and tactile with these ancient sea animals.

As the corals cant take being out in the sun for too long, it was time to get them back under their moist towels and head to their recipient site at Sisters Island.

It took a handful of people to safely and gently lower the loaded coral baskets back into the water.

Once back on the reef, our job is to find a new home for our corals. It’s like a wild 3-dimensional jigsaw puzzle was we rotated corals around and scouted all areas of the reef that would be a nice fit for the base of the corals, like the one in the photo above! You almost can’t tell that the boulder coral isn’t actually growing on the reef!

Here’s what it looks like after we stuck it up with cement.

Here’s a plate coral and boulder coral before cementing…

And after cementing. It may look a bit messy now, but after installing all the corals, we swam over to other parts of the reef where other volunteers had been planting harvested corals since the middle of past year. Once the coral has fastened itself back onto the reef, and algae and other encrusting material take over the cement, it is almost impossible to tell that that coral was artificially installed! But it also means that really good sites were chosen for us for the relocation by the scientists at DHI!

Some curious butterflyfish came close while we were installing the coral

Another newly installed coral colony

The reefs of Sisters Island already have many large and beautiful coral colonies! Most of them, like this one, had more than one maroon-coloured crinoid perched on top of the colony! And what great vis! It really allowed us to enjoy the dive and observe the entire reef scape. There was a lot of activity! Divers saw at least two pufferfish, schools of parrotfish feeding, and damsels getting cleaned by wrasses

There were three Blue-spotted fantail rays too! Two in crevices such as this, and one that was free swimming in the water! It swam past too fast for me to grab a pic! But they look so gorgeous when they are swimming.

There were also many nudibranches and flatworms. What a special opportunity it was to be a part of this project. The Hantu Blog is very pleased to participate in these activities that are usually reserved for scientists, as well the rare privilege to dive a part of Singapore waters that is usually closed off to the public! I look forward to re-visiting the reefs at Sisters to find out how well the corals we transplanted today have adapted to their new home.

To learn more about the Tuas reclamation project, see Ria Tan’s post.

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