Sentosa Tg Rimau still alive but quiet

We return to a beloved Sentosa shore, 1.5 years after the 400tonne Pasir Panjang oil spill in Jun 2024. I feel the shores were quieter compared to our survey in  Aug 2024  two months after the oil spill.

While seagrasses are doing well on the eastern side, on the western side, the Tape seagrass are cropped short. There seemed to be fewer hard and soft corals on the eastern side. The team saw interesting marine like the Tiger cowrie, many crabs and fishes. I will update with their sightings after they share their photos.

As usual, the rest of the team make all the special finds. Lon found a Tiger cowrie! Also an Arabian cowrie as well as colourful reef fishes. The usual slugs were seen. And anemones like Giant carpet anemone, Haddon's carpet anemone and Frilly anemones. An Upside down jellyfish was also seen - in the past, we only commonly saw this further south. As the sun set, the octopuses came out to hunt!

Collage of photos by Lon and Rui Quan
Links to their albums below

Despite the heavy shipping traffic next to this shore which includes very large cruise ships, it is still very much alive. There were many colour crabs of all kinds, heartening to see juvenile snails which suggests the shore is a good nursery. The rocky shores were also alive with large Jewelled chitons, Giant top shell snails, and many colourful snails commonly seen on our rocky reefs. Was a relief that Big onch slugs were seen.

Collage of photos by Lon and Rui Quan
Links to their albums below

The sandy areas on the eastern shore were alive too. We saw a few Common sea stars, many sand dollars. Special finds include two Strawberry cockles, our first sighting on this shore. Also an Olive snail we have not seen before - seems to be same one Kok Sheng saw in Oct 2025.

Collage of photos by Lon and me.
Links to their albums below

There have never been a lot of corals on this shore. Today, I sense there were even fewer corals than before. Although there are still a variety of common corals, mostly boulder-shaped ones including a few large colonies. Most of the corals I saw seemed alright, I didn't see any bleaching corals. 

On the eastern shore, there were much fewer hard and soft corals compared to our survey in Aug 2024  two months after the 400tonne Pasir Panjang oil spill. On the western shore, I saw more corals, mostly small hard coral colonies and medium sized leathery soft corals. There were also very small colonies of hard and soft corals - hopefully suggesting recovery? 

Sentosa Tg Rimau has among our last natural cliffs with natural rocky shores. The rocky eastern shores still had lots of nerites and large chitons, but the western rocky seemed quieter. A natural coastal forest cloaks the cliff. Hardy plants grow here. Sentosa's coastal forest has some of the last of Singapore's now rare coastal plants. 

Among them is Nyireh laut which is Critically Endangered in Singapore and we probably have less than 10 trees on our shores. The mother tree looks a little less leafy, but otherwise seems okay. Her oldest Daughter no. 1 next to her is still alright with fresh green leaves. The next younger Daughter no. 2 growing near the pill box is growing tall with fresh green leaves. Daughter no. 3 which I last saw as a sapling in Apr 2014 has grown really tall with fresh green leaves. Today, I managed a look at her trunk! And Nasry pointed out what could be Daughter no. 4 nearby!

Erosion, slope failure and rock slides are a natural aspect of such cliffs. These can kill the precious plants and trees that grow here.

On the eastern shore, there are still many clumps of long Tape seagrasses (1m), one clump was seen with fruits. On the western shore, Tape seagrasses are still widely present but most of them are cropped short (under 10cm) or only moderately long (to 20cm). I didn't see any with long leaves. I didn't manage to check the seagrases near the seawall at Rasa Sentosa. 

On the eastern shore there were still some Sickle seagrass leaves not cropped. Dense cover of Spoon seagrass (tiny leaves) cover most sandy areas among the rocky shores. On the western shore, seagrasses are still lush on the mid water mark. Lots of Spoon seagrasses (tiny leaves), some Needle seagrass (narrow leaves). 

I'm trying to be more diligent about documenting seaweed blooms. Today, on the eastern shore, Sargassum is still in bloom, outlining the reef edge - these naturally bloom every year end. There was also a bloom of Halimeda green seaweed poking out from a dense cover of some other kind of seaweed - this covered and area about 10m. The entire western shore continues to be blanketed in a Bryopsis bloom which seems to be going on all the time, for some years now. We noticed this on other shores too, where Bryopsis blankets some portions of the shore while others are free of the seaweed.

Hope the shore can recover by the time we survey again!

Photos by others on this survey

Rui Quan Oh


Lon Voon Ong


Others on this survey: Muhd Nasry, Yin Chuan, Samuel Lau, Yan Le