Some bleaching at Sentosa Serapong

One of the best reefs nearer the mainland is found on the undisturbed shore off Serapong Golf Course at Sentosa. We did not notice a lot of bleaching until we approached the end of our survey. We estimate about 10% were outright bleaching.

Relieved to see lots of healthy corals near the slipway.

Today, I had a chance to share these shores with friends from Sentosa Development Corporation. Thanks to SDC for being such good sports during the walk, and for supporting our surveys through all the years!

I can't survey and guide at the same time. So I am grateful some volunteers could focus on surveying. Here's some by Kok Sheng: from the Tomato anemonefish (sadly in a bleaching Bubble tip anemone), to flatworms, octopus and even a funny looking shorebird (Masked Lapwing!).

Collage of photos by Loh Kok Sheng.
Link to his album at the end of this blog post.

Kelvin found a large Giant clam (about 30cm long)! Good to know they are still here. He also checked up on the big colony of Acropora near the beacon - seems pale but not yet full on bleaching. Also the flatworms, nudis and other interesting marinelife some of the rest of the team saw.

Collage of photos by the team.
Links to their albums at the end of this blog post.

In 2018, we observed mass dying at Serapong, and only at Serapong - cause still unknown. Many corals hard and soft, as well as large sponges were dying. We observed a somewhat full recovery during our last survey in May 2023. Today, it was great to see some medium-sized to large healthy Barrel sponges - these suffered badly during the Big Dying. 

Unfortunately, this year, mass coral bleaching is expected to hit all our shores soon and signs suggest it has arrived at Serapong. The corals at the beginning of our route were generally alright. There are two patches of dense Branching montipora corals - one infront of the spillway and the other further to the side. Both were not bleaching - we saw these corals bleaching on Beting Bemban Besar yesterday. Cauliflower corals are usually among the first to bleachi, but today we saw many and they seemed mostly alright, although some have dead patches. These were wiped on it the Great Dying in 2018 and returned during our last survey in May 2023. Sandpaper coral and Anchor coral are also often among the first to bleach and we saw healthy ones today.

It was a relief to see that there are still many large colonies of Anemone coral here. Most were not bleaching, although some had dead portions and a few were starting to bleach. 

We did see a few bleaching or stressed hard corals, but it was only when we approached the Old Jetty that we started to see more extensive bleaching. The large colonies of Ridged montipora corals were all bleached. But lots of red feather stars still festooned them. 

This is what the Ridged monitopora coral in this area looks like when they are happy. They recovered from the Great Dying in 2018 and were well during our last survey in May 2023. So hopefully, they can recover from mass coral bleaching too.

Thanks to Kok Sheng for surveying past the Old Jetty all the way to nearly the Causeway Bridge. Seems there are large patches of corals here. Some are starting to bleach.

Photos by Loh Kok Sheng.
Link to his album at the end of this blog post.

Kok Sheng saw a wide variety of corals, including some special ones. Some showed signs of stress, a few were outright bleaching, while others seemed alright.

Photos by Loh Kok Sheng.
Link to his album at the end of this blog post.

There remains many leathery soft corals of various kinds, some were quite large. While some had pale patches, or were breaking up (a sign of stress) only a few were outright bleaching. The large Leathery soft coral in the middle of our route seemed to have fragmented into smaller portions.

But almost all the Flowery soft corals I saw throughout the shore were pale and many near the Old Jetty were bleaching. It's surprising to see Mushroom corals and other corals that were NOT bleaching among these stressed soft corals. I would estimate about 10% of the flowery soft corals were NOT bleaching or stressed - showing their usual array of pink, orange or red colours. 

Other cnidarians can also bleach, so I looked out for those too. One Giant carpet anemone was a little pale, the rest I saw were okay. The large patch of Magnificent anemones near the Old Jetty were alright - I have never seen these anemones bleach even in full blown mass bleaching events. Some sea mat zoanthidssea mat zoanthids were pale. High res photos of mass coral bleaching survey on wildsingapore flickr.

I saw 3 clumps of Tape seagrass with long leaves, only 1 had rather cropped leaves (but not cropped very short). All had developing female flowers. We only saw a little Sickle seagrass near the beacon, and sprinkles of Spoon seagrass all along the shore.

These corals and many others on the shores, were badly hit during the Great Dying in 2018. And recovered about 5 years there after. So I hope they will recover from this mass coral bleaching too.

Thank you SDC and Serapong Golf Course for supporting our annual surveys and for looking after these precious shores!

Photos by others on this survey

Loh Kok Sheng


Che Cheng Neo


Tommy Arden


Kelvin Yong Part 1

Part 2


Ng Lee Kiang


Tommy Tan


Ng Leekiang