13 January 2021

Pulau Semakau (West) with giant clam

We return to this stretch of Pulau Semakau which used to be regularly visited as it is part of the public walk trail.
Living shores of Pulau Semakau (West)
It was great to see a large giant clam, healthy corals and interesting marine life. Despite the tide not being as low as predicted. Unfortunately, there remains very little seagrass in the area.

It was a thrill to see a huge Fluted giant clam! This healthy clam was about 40cm long, nestled among large leathery soft corals. It reminds me of Mama Jong, the large giant clam on Pulau Jong, who died in 2018.
Fluted giant clam (Tridacna squamosa)
There are not many hard corals on this part of the shore. But those I saw were healthy.
Near the reef edge, I saw many large leathery soft corals. All looked to be in good health.
I was glad to see familiar animals like Common sea stars - which are no longer as common on our shores as in the past. I saw many Frilly sea anemones and one Giant carpet anemone. I also saw one young Noble volute and several common nudibranchs.
On the dreary day, colourful sponges were a bright spot.
But it was sad to see that seagrasses have not recovered. There used to be a large meadow of long Tape seagrass on Pulau Semakau. Here's what it looked like when TeamSeagrass started monitoring the seagrasses here in 2007.
TeamSeagrass at Semakau's vast seagrass meadows
The highlight of the public walk in the past was walking through thick growths of very long Tape seagrass, as in this photo taken in 2008.
Crossing the seagrass meadow at Semakau
To minimise the impact of the walks, a path was designated between two rocks so people crossed this patch of seagrass only on along this path.
'Death zone' path through seagrass meadows
Today, the area between the two rocks were bare of seagrasses (indicated by yellow arrows in this photo). I first noticed Tape seagrasses on Pulau Semakau being cropped short in Jun 2012, and more obviously in Oct 2014. Since then, long Tape seagrasses all over the island have disappeared, although cropped blades are still seen.
Seagrasses missing at Pulau Semakau (West)
Today, I saw very few clumps of Tape seagrasses, all were cropped. There were sprinkles of Spoon seagrass (small leaves), small patches of Needle seagrass, and some Sickle seagrass.
As we arrived, the team spotted what looked like 6 otters swimming in the shallow waters! Here's Jonathan Tan's photo of them.
Could these be the descendants of the lone otter that I first saw here in 2011? Another bittersweet memory for me as Subaraj first spotted the otter. As we were getting ready to leave, Alex pointed out two sea turtles which came up briefly to the surface.
Lone otter I saw at Pulau Semakau in 2011.

It a dreary day in a tide that didn't fall as low as predicted. But it didn't rain, the monsoon surge that brought non-stop rain seems to have eased. And the Sargassum bloom on the shore seems to be over.
Living shores of Pulau Semakau (West)

Public walks at Pulau Semakau

I got to know this part of Pulau Semakau well when I started public walk programme here in 2005. I have not surveyed this part of Pulau Semakau since Apr 2016.

I believe you can still join a guided intertidal walk at Pulau Semakau today. Contact the Lee Kong Chian Natural History Museum or Strix Wildlife Consultancy for more details.

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.
Map of Pulau Semakau, Pulau Hantu, Pulau Jong and surrounding submerged reefs

Photos by others on this survey

Jianlin Liu


Vincent Choo


Jonathan Tan


Others on this survey: Arjun.