Pulau Semakau (North) doing well

A full team surveys the rich reefs of Pulau Semakau (North). 

We last surveyed in Jul 2024 to check for impact of mass coral bleaching. At that time, we estimated about 20% of hard corals were bleaching, with a few bleaching leathery soft corals. Today, we didn't see any bleaching corals. The team spot Giant clam, large Cushion stars, sharks, sea turtles and more! But we also observed scummy water.

As usual, the rest of the team make all the special finds. The Giant clam is still there. Richard spotted Razorfish among the long spines of the Diadema sea urchin. Plus lots of large cushion stars, red feather star. 'Nemo' plus the usual colourful slugs and flatworms. We all saw small sharks near the reef edge, and one in the large pools where the seagrasses used to be. Alex told us he saw about 5 sea turtles from the boat! 

Photos by Richard Kuah and Tammy Lim.
Links to their albums at the end of the blog post.

The reef edge remains rich with many well formed healthy corals like Goniopora corals. There were still some kinds which are not often seen on our shores. Most seemed alright today. I saw many mushroom corals at the reef edge, including tiny ones still attached to a hard surface - all seemed well. I saw Anchor corals, Trumpet corals, Brain corals, all seemed fine although some colonies had dead portions. I did see a few colonies that were pale or pinkish, and some with scattered white patches.

Today, I saw many Leathery soft corals on the reef edge of various kinds. I didn't see any that were bleaching.

I saw the usual common anemones, none were bleaching: Bubble-tip anemone, Giant carpet anemones, Fire anemone, Haddon's carpet anemones. Also upside down jellyfishes. The the Sea mat zoanthids I saw were paler than usual.

I also briefly checked the seagrass situation at Pulau Semakau (West) north of the stream. I came across what seemed to be TeamSeaGrass Site 1 stake! The situation seems similar to what I saw in Jun 2023. Today, the middle of the shallow lagoon was almost completely bare, with very few clumps of Tape seagrasses, all were cropped. At the mid-water mark near the high shore, there were sprinkles of Spoon seagrass (small leaves) and other seagrasses, all heavily covered in epiphytes. At the reef edge, I did see small clumps of Tape seagrasses with longer leaves (about 30cm). I briefly walked through what used to be the seagrass area south of the stream before sunrise. There is still virtually no seagrasses.

Today, we saw patches of sudsy scum at the water line on both sides of the stream draining out of the island.

I didn't notice any smell from the scum. Not sure what is happening.

There was flaring on Jurong Island. More visible today from Pulau Semakau. I also noticed this at Pulau Hantu yesterday but couldn't see the flame from there - only the orange glow in the emissions from the flare.

More about Pulau Semakau

Just as Changi Airport and Changi Beach are not the same even though they are near one another and share a name, Pulau Semakau is NOT the same as the Semakau Landfill. The Landfill was created by destroying all of Pulau Saking, and about half of the original Pulau Semakau by building a very long seawall. Fortunately, the landfill was constructed and is managed in such a way that the original mangroves, seagrass meadows and reefs on Pulau Semakau were allowed to remain. It is NOT true that the construction of the Landfill created the marine life found on Pulau Semakau. The marine life was there long before the Landfill was built.

What is the fate of Pulau Semakau (North)?

Pulau Semakau (North) is likely to be affected by the 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

Tammy Lim


Richard Kuah


Others on this survey: Kelvin Yong, James Koh, Liz Lim, Tommy Tan, Ian Mun, James Cabatbat, Amy Woon.