25 May 2024

Sentosa Tg. Rimau is still alive!

A small team checked up on Sentosa Tg Rimau with kind permission from Sentosa Development Corporation.
Sickle seagrass (Thalassia hemprichii)
Although it lies just opposite the Pasir Panjang Container Terminals, there are lush seagrasses here. I checked for mass coral bleaching. I estimate only about 2% of corals hard and soft were outright bleaching.

As usual, the rest of the team made all the special finds. Kok Sheng spotted two Tiger cowries that was last seen in 2020. There are still a lot of octopuses. And a night trip means we see more fishes which are not so shy in the dark.  Also nice to see the usual reef life such as crabs, nudibranchs, slugs, flatworms.
Collage of photos by the team.
Links to their albums as the end of this blog post.
My mission was to check for mass coral bleaching which is expected to hit our shores soon. There have never been a lot of corals on this shore. But there are still a variety of common corals, mostly boulder-shaped ones. Most of the very large colonies here were nice and brown.
Mass coral bleaching 2024 check on Sentosa Tg Rimau, May 2024
In fact, most of the hard corals I saw were alright. Some were pale or had patches of bleaching. I estimate only about 2% were outright bleaching - whole colony bleaching.
As on my last survey in Apr 21, I saw many leathery soft corals colonies of a wide variety, most were medium-sized but there were many small colonies scattered on the shore. Most were alright, although some had pale patches. I only saw one whole colony bleaching, towards the reef edge. High res photos of all hard and soft coral sightings on wildsingapore flickr.
Other cnidarians can also bleach, so I looked out for those too. Frilly anemones are the most common anemone here. Today, we saw a few bleaching ones, but most were alright. I saw corallimorphs that were alright. Although some of the Chocolate sponge I saw had dead patches - I saw these sponges with freshly dead patches on our survey of Terumbu Raya earlier in the month.
Collage of photos by the team.
Links to their albums as the end of this blog post.
The natural coastal forest that cloaks this natural cliff 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 only about 7 trees on our shores. The mother tree and her older daughter tree are still alright (green arrow). I first saw a large landslide near them (yellow arrows) in Apr 21. Landslides are normal on a natural cliff and it's great the rare trees have not been wiped out in one (yet?). The patch of Raffles pitcher plants are also still there. I didn't check up on  the very young Nyireh laut that has settled under the cliff some distance from the mother tree is still doing well. I first saw it in July 2017 and it was okay on my last survey in Jan 2023.
Seagrasses are still lush on the mid water mark on this shore. Dense cover of Spoon seagrass cover large areas, I saw some Needle seagrass too. Near the seawall at Rasa Sentosa, the patch of Sickle seagrass is still doing well. 
Tape seagrasses are still widely present but many of them are cropped short (under 10cm) or only moderately long (to 20cm). I only saw those with long leaves near Rasa Sentosa. Though I didn't see any ongoing flowering, I did come across some female flowers that bloomed, and fruits, one unopened and one opened.
The bloom of Bryopsis green seaweed seems to be never ending, we see it all the time for many years already. But it does mean that we get to see a lot of the Bryopsis slug - photo of the slug by Loh Kok Sheng.
Let's hope this shore stays safe until we can visit again. Thanks to Sentosa Development Corporation for permission to survey and accompanying us on the shore.


Photos by others on this survey

Loh Kok Sheng


Richard Kuah


Tammy Lim


Che Cheng Neo


Tommy Tan


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