St John's Island doing well

Just minutes from the Central Business District, lies one of Singapore's last natural cliffs at St John's Island. The rocky shore and reef edge has corals. There are also seagrasses throughout, as well as rare mangrove trees on the untouched western shore, which is part of the Sisters Islands Marine Park.

Today, the corals seemed fine, seagrasses still doing well. The rest of the team find special snails, 'Nemos' and other interesting marine life. 

I have never seen a lot of corals on this shore since I started surveying it. Most are boulder shaped, with common plate corals, mostly small to medium sized, but also a few very large colonies. Today, I saw the usual assortment and all seemed fine. This is a relief as during our last survey in Apr 2025, almost all the boulder Pore corals large and small were very pale. They were bone white and NOT glowing white as bleaching corals would do. Today, I didn't see any corals in this situation.

As in the past, I saw a variety of small to medium-sized colonies of leathery soft corals. Those I saw today seemed alright. I also saw two colonies of Leathery sea fan both were fine. As in the past, I didn't see any Flowery soft corals. We noticed an explosion of the Magnificent anemone population during our last survey in Apr 2025, and they are there, still small for now - but when they grow bigger, might overwhelm the shore as these do on our other reefs. I saw many Giant carpet anemone throughout the rocky shores. There were also a variety of sponges including small Barrel sponges. All seemed fine.

The rest of the team saw some special corals and well-formed healthy common corals. They documented more individuals of the explosion of the Magnificent anemones first observed on our last survey in Apr 2025. There were clown anemonefishes aka 'Nemo' in these as well as Giant carpet anemones. Many Pimply phyllid nudibranchs were seen, from tiny to normal sized. And a special flatworm too. But no other common nudibranchs.

Photos by the rest of the team, links to their albums below.

The rest of the team saw lots of interesting marine life on the natural rocky shore. A Cone snail and a Vitate conch, and Swimming file clam - we rarely see them. There were many Arabian cowries, and Richard found a juvenile. After dark, lots of octopuses and Jeweled chitons became active. Also some small groupers hiding among the rocks, as well as a flathead. Giant reef worms seemed active too. There were many common crabs like Red and Brown egg crabs, but also Sally lightfoot crabs which are not so commonly seen. Kelvin spotted a Paddler crab clinging onto a coconut - it is freshwater crab but adults return to the sea to hatch their eggs and are often seen clinging onto flotsam.

Collage of photos by the rest of the team.

The sandy artificial lagoons are alive! Dotted with tiny Bazillion snails, and burrows of Sand bubbler crabs, mudskippers active during daylight. As it got dark, on the lower shore among the tiny seagrasses Ghost crabs emerged to hunt, while small fishes sheltered in pools. There were still some Common sea stars, some live Gong gong snails and many Oval moon snails with a few other special moon snails. 

Collage of photos by the rest of the team.

The real treasures are the grandmother Nyireh laut tree and her daughters that grow on the western shore of St John's Island, which overlooks the Sisters and is part of the Sisters' Islands Marine Park. Nyireh laut is Critically Endangered in Singapore and we probably have only about 7 trees on our shores. There are another 3 on Sentosa Tg Rimau. We checked on them in Jun 2024 just after the Pasir Panjang oil spill, they were okay: no smell or stains of oil on their trunks, leaves still fresh and green. Today, they are still fine, although the large wooden pallet is still lodged near one of the daughter trees. Che Cheng saw a fruit developing on the mother tree!

St John's Island has one of the few remaining natural coastal forest, growing on natural cliffs leading onto a natural rocky shore with corals and other marine life. It is also natural for landslides to occur. Although these take out trees that grow there, these also produce the wonderful boulders and pebbly shores that we find so pleasing.

Seagrasses here seem fine! Outside the seawall of the swimming lagoons, I saw clumps of Tape seagrass with long leaves (30-50cm), one with developing female flowers.  St John's Island is one of the few shores left that still has long Tape seagrass. Inside the swimming lagoons, and on sandy patches in the natural rocky shore, there are large patches of Spoon seagrass with small leaves, I missed seing Needle seagrass today. There were also sprinkles of Spoon seagrass throughout the rest of the shores. On the Western shore facing Sisters Islands, there are still sprinkles of Sickle seagrass among the rocky areas. All seagrasses looked fresh and green and healthy.

The annual Sargassum seaweed bloom is just starting up. Today on St John's Island, the seaweed getting fluffy at the reef edge near the jetty. It is not yet in 'full bloom' at which point they form thick carpets with long strands which can wrap around legs and make surveying the reef edge impossible to do safely. But I didn't see much growth on the natural rocky shore, even around the corner to the shore facing the Sisters Islands. I'm tracking the bloom season as we feel that in recent years, it is starting earlier and ending later.

Thanks to Che Cheng for this great photo for a buoy that we noticed off the western shore of St John's Island. This buoy that is part of the Marine Environment Sensing Network (MESN) with sensors to collect 24/7 data. Kind of like a weather balloon, it monitors a wide range of marine parameters.

The St John's Island jetty is closed, ostensibly until Mar 2026. Fortunately, we are able to make amphibious landing thanks to Alex who waits patiently for us just off the jetty.

St John's Island in the Singapore Blue Plan

The Singapore Blue Plan 2018 highlights the importance of St John's Island to our marine biodiversity. The cluster of Kusu, Lazarus and St. John's Islands has been recommended by the Singapore Blue Plan 2018 for elevated protection status.

The Sisters Islands on the horizon.

The Blue Plan highlights that Lazarus, St. John’s, and Kusu Islands are established sites for coral nurseries as their shoreline offers ideal sheltered areas for growth of corals. Designating these islands as No-fishing Areas can bolster their rehabilitation. Protecting a larger cluster of islands means 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 those on the survey


Richard Kuah




Lon Voon Ong


Jianlin Liu


Adriane Lee


Loh Kok Sheng


Kelvin Yong


Che Cheng Neo

Tammy Lim