Pulau Semakau (North) with 3 giant clams

Pulau Semakau (North) is close to the petrochemical plants of Pulau Bukom and yet has some great reefs. A full team survey today and find 3 giant clams, a seahorse, special sea anemones and more. 

The corals seem mostly alright although there are signs of stress in some colonies. The seagrasses remain sparse.

Return to Pulau Semakau (South) mangroves

A full team surveys here at predawn for the first time! The original mangroves, seagrass meadows, and reefs of Pulau Semakau lie next to the Semakau Landfill. They are very much alive.

We land next to the Landfill wall, on living seagrass meadow at first light of a glorious sunrise! The rest of the team find a healthy reef on the edge, lots of fishes and other interesting marine life. The ongoing Sudong reclamation looms in the distance.

Pulau Semakau (West) in the face of Sudong reclamation

The full team survey this stretch of Pulau Semakau which used to be regularly visited as it is part of the public walk trail. We are trying to check this shore out more regularly.

I checked on the mangroves for the first time in a long while, with the massive reclamation at Pulau Sudong on the horizon. We still find Giant clams, seahorse and other interesting marine life. The rest of the team make all the special finds, I will update with their sighting later on. The corals seem okay. There were lots of lively sharks and sea turtles in the water too. The seagrass situation, unfortunately, remains unchanged.

Other intertidal surveys in Feb 2026

Between the low spring tides, the intrepid Rui Quan Oh relentlessly checked out more shores! As usual, I learn a lot about crabs, and also the pretty insects and spiders of our mangroves. So glad to know cute fiddlers and awesome Blue-spotted mudskippers still abound on Pulau Ubin. 

Collage of photos by Rui Quan Oh

Rui Quan checked out Sentosa, Coney Island, Admiralty Park. And also Ubin together with Zen Xuan He. Thanks also to Dr Clarence Sim for inviting Rui Quan to help in his intertidal work at Pulau Semakau.

Giant clams at Pulau Semakau (East)

One of the reefiest shores lies next to Singapore's only landfill and near petrochemical plants on Pulau Bukom. A team surveys even though the tide was not as low as we expected.

The corals seemed alright and we find 6 Giant clams! There were also lots of large sea anemones, colourful crabs, nudibranchs and other interesting marine life.

Pulau Semakau (West) is still alive

The full team survey this stretch of Pulau Semakau which used to be regularly visited as it is part of the public walk trail. We arrive at sunrise for a brief low tide window.

We didn't get a chance to survey the shore during mass coral bleaching last year, so it was relief to see the corals seemed alright. Special finds include an elusive anemone, a Giant clam and other interesting marine life. There were lots of lively sharks and sea turtles in the water too. The seagrass situation, unfortunately, remains unchanged.

Recovery at Pulau Semakau (East)

When we last surveyed in Jul 2024, the shore was impacted by mass coral bleaching. We estimate 50% of hard corals and 70% of leathery soft corals were bleaching. Today, it was such a relief to see that the shore was NOT dotted with white. Most of the corals were okay and the reef seems have recovered to its usual vibrant self.

The team found 4 Giant clams, encountered shark and snakes as well as many other interesting marine life.

Pulau Semakau (South) - seagrasses doing well!

A tiny team survey this shore right next to the Landfill in glorious weather.

The seagrasses are still doing well! Corals seemed to have survived mass coral bleaching, and the 'field' of branching coral seems to be expanding. Ian managed to document a large sea turtle and large shark! 

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.

Pulau Semakau (South) returns to life?

After a heavy downpour, we survey the living shores next to the Landfill at Pulau Semakau South.

The seagrasses seem more lush - with signs of dugong feeding trails! A patch of healthy branching corals are forming, corals seemed to have survived mass coral bleaching. And the field of Horse mussels that infested the area seem to have totally disappeared. Perhaps the closure of the fish farm had something to do with this?

Oil spill from Bukom refinery, 20 Oct 2024

Oil slick and sheen is seen in surrounding waters due to leakage from a land-based pipeline between Bukom Island and Bukom Kecil which happened early morning 20 Oct 2024. 

Shell stopped the leak at source, placed containment booms off the site of the leak and deployed craft equipped with dispersants to clean up the oil sighted in the vicinity of the leak.

MPA deployed 7 MPA craft to spray dispersants. As at 6pm 20 Oct 2024, no new oil sightings were reported. From media reports as below.

Mass coral bleaching at Pulau Semakau (North)

The team surveys the rich reefs of Pulau Semakau (North). They encounter Giant clam, large sea stars, large snails and other interesting marine life.

We estimate about 20% of hard corals were bleaching and are relieved to see very little recent death, with many large colonies at the reef edge still healthy. Unfortunately, seagrasses remain sparse. Kelvin also flew the drone for unique overviews of the situation.

Mass coral bleaching at Pulau Semakau (East)

At a not-so-low-tide before dawn, we survey Pulau Semakau next to the Semakau Landfill and near petrochemical plants on Pulau Bukom.

Despite its location, this shore has living reefs with giant soft corals, giant sea anemones and we saw 2 Giant clams! Unfortunately, it is impacted by mass coral bleaching. We estimate 50% of hard corals  and 70% of leathery soft corals were bleaching. Kelvin also flew the drone and will have valuable insights into the situation.

Semakau (South) is alive

On a rare evening low tide, we survey the living shores next to the Landfill at Pulau Semakau South. 

Here, there are corals, seagrasses and mangroves which seem to be hanging on. We narrowly escaped a lightning storm at the end of our survey and got back on the boat just in time.

Sharks at Semakau!

There is a rich reef on the northern corner of Pulau Semakau near Pulau Hantu and Pulau Bukom. 

Kelvin gives us a new perspective of the shore from a drone! The survey team saw lots of sharks, giant clams, 'Nemos', tiny sea horse and other amazing marine life. The corals seem to be doing well, but the seagrasses have not recovered.

Southern fish farm to stop due to deadly virus

Barramundi Group will stop stocking its sites off Pulau Semakau, Pulau Senang and St John’s Island until “an efficacious vaccine is available” against the scale drop disease virus (SDDV). 

From  The Straits Times 31 Jul 2023

SDDV was first formally described in Singapore farmed fish in 2011 and can kill more than half of the barramundi raised in a cage. The virus has caused “significant mortalities and financial losses” for Barramundi Group's Singapore operations, which recorded a loss of $31.9 million for FY2022. 

More details in the excellent article by Ang Qing and Shabana Begum The Straits Times 31 Jul 2023

Pulau Semakau (East) is alive!

On a hot morning, we survey Pulau Semakau next to the Semakau Landfill and near petrochemical plants on Pulau Bukom.

Despite its location, this shore has living reefs with giant soft corals, giant sea anemones and we saw 1 Giant clam!

Pulau Semakau (West) with Knobbly sea stars

A small team survey this stretch of Pulau Semakau which used to be regularly visited as it is part of the public walk trail.

We were glad to see Knobbly sea stars which used to delight our visitors. Kok Sheng found a Giant clam! Kelvin saw a sea turtle from the drone. The corals are doing well and we see the usual marine life. Sharks and sea turtles are spotted too. Unfortunately, the seagrasses remain sparse on the shore.

14 dead sharks at Pulau Semakau South

There are living shores next to the Landfill. With corals, seagrasses and mangroves. A small team pushes through the Sumatra storm to arrive just after it passed.

Unfortunately, we encountered an abandoned net with 14 dead sharks, an expansion of the field of horse mussels, and sightings of bleaching anemones and pale corals.

Mussels taking over Pulau Semakau (South)?

We survey the seagrasses and shores at Pulau Semakau South on a lovely evening low tide. 

The corals seem alright. Although Tape seagrasses have not returned and vast stretches remain bare of seagrasses, there was good seagrass growths near the landfill wall. It was worrying to see Horse mussels continue to expand on the shore.