Pulau Jong is alive!

A large team survey this untouched island, landing at sunrise. Corals seem to be okay, we didn't see any mass coral bleaching.

The tide window was narrow but the team managed to find many Giant clams and other amazing colourful marine life. I will update with their observations later.

This last pristine island lies just minutes from the Central Business District. As usual, the rest of the team make all the special finds: large cowries, interesting brittle stars and large sea urchins. Cute hermit crabs, colourful crabs and strange sea anemones. There are stingrays and sharks (see Che Cheng's video below). And also one Long-tailed macaque - we saw two in the past.

Collage of photos by the team.
Links to their albums below.

Thanks to Che Cheng for this awesome clip of a peaceful shark excited to hunt for fish in water so shallow, its fins are sticking out. Our sharks are NOT dangerous to humans. They will U-turn as soon as they notice us. Sharks are a sign of a healthy reef. Many sharks means there is enough fish for them to eat. So let's rejoice when we see sharks on our shores!

The rest of the team not only spotted many different kinds of nudibranchs, Jianlin also document eggs by some of them! Everyone saw many small Polka-dot nudibranchs too, and Rachel saw what might have been their egg ribbon. There were also other kinds of slugs, and some colourful flatworms too.

Collage of photos by the team.
Links to their albums below.

Pulau Jong is very much alive, even though it lies near petrochemical plants on Pulau Bukom, the Landfill and major shipping lanes. It is mostly rocky shore which is a surprisingly great place for Giant clams to settle!

Update on Giant clams found: 6 Fluted giant clams including a new sighting of a large one on the reef edge found by Rachael (bottom right), and a small one (about 10cm) found by Marcus. The others are known clams. The collage below of photos by the team omits one which didn't have a clear photo. They seem well.

Collage of photos by the team.
Links to their albums below.

Here's the two large Fluted giant clams (about 30cm) that we have seen before. I went to pay my respects Mama Jong but couldn't even find the stick that marks her location. This enormous Giant clam is called Mama Jong because her babies were a part of Dr Neo Mei Lin's work. She has been loved and monitored for a long time. We found her dead on our Jun 2018 survey, and in Aug 2021, even her shells were no longer at the spot where she was. We are glad the Giant Clam team from TMSI was on our survey to take proper records of these awesome animals.

Similar to our survey in Aug 25, today I saw some small and medium-sized leathery soft corals of various kinds. There used to be many very large colonies here, but I noticed a decline in Aug 2020. In Jan 2023 is noticed some large colonies and in May 2024, there remained many medium sized colonies but no large colonies. I didn't see any that were bleaching. I also saw the other usual cnidarians such as Asparagus flowery soft corals. Large areas of the shore was covered in button zoanthids as well as Sea mat zoanthids - some were very pale but not bleaching.

I have never seen a lot of hard corals on Pulau Jong since we started surveying it. Today, there were the usual variety of commonly seen species, most were boulder shaped. Most seemed alright, I didn't see any that were outright bleaching.

As usual, there were many Boulder pore corals from very large colonies to smaller ones. Most seemed alright, although some were a little paler. And a few had black fluffy stuff growing on holes which are commonly seen on this corals made by burrowing animals (these typically leave a pink ring of live tissue around the holes). Thanks to Dr Clarence Sim for pointing this out. Not sure what is happening.

There are still sprinkles of Sickle seagrass and Spoon seagrass on the south-eastern edge of the island. I forgot to take photos, so thanks to Dr Clarence Sim for these photos. They were fresh and green although some were covered in the pale brownish fuzz that Dr Sim says might be long-chain diatoms.

Photos by Dr Clarence Sim.

Recently, I am keeping track of Sargassum bloom on our shores as they seem to start earlier and end later. Today at Pulau Jong, there were still longer strands of the seaweeds in the middle of the reef flats, although the rest of the shores were mostly clear.

Untouched by reclamation, Pulau Jong is one of the last islands where you can find the full spectrum of coastal ecosystems that used to be found in Singapore. Coastal forest growing on natural cliffs full of native plants, along a shore with corals and marine life. Today, the tide window was too narrow for me to look at the forest. 

What is the fate of Pulau Jong?

Pulau Jong as well as Terumbu Semakau and much of natural Pulau Semakau is slated for massive reclamation outlined recently in the Long-Term Plan Review.

The Singapore Blue Plan 2018

Pulau Semakau and nearby islands and submerged reefs have been recommended by the Singapore Blue Plan 2018 for Immediate Conservation Priority.

The Blue Plan recommends the intertidal and subtidal marine areas of Pulau Semakau and adjacent Pulau Hantu, and Pulau Jong to be designated Marine Reserve.

The Blue Plan highlights that Pulau Semakau and its associated patch reefs comprise many ecosystems: coral reefs, mangrove areas, intertidal sandflats, seagrass meadows, and coral reefs. The subtidal area of Pulau Jong is larger than the terrestrial area. Pulau Hantu is a popular dive site has seen increasing interest in the past decade due to biodiversity awareness. If protection is accorded to these three islands, zonation plans for use can be implemented to manage tourism and human impacts.

DOWNLOAD the Plan, SUPPORT the Plan! More on the Singapore Blue Plan 2018 site.

Photos by others on this survey

Richard Kuah


Che Cheng Neo


Marcus Ng


Jianlin Liu


Rachael Goh


Rui Quan Oh


Tammy Lim



Lon Voon Ong


Samuel Lau


Jason Ooi


Zen Xuan He


Tommy Tan



Others on this survey: Ian Mun, Dr Clarence Sim, TMSI Gian Clam team.