09 June 2012

Special anemones at Terumbu Semakau

The drizzle didn't dampen the spirits of a small team out to explore Terumbu Semakau this morning. This large submerged reef lies right next to the Semakau Landfill! And yet it is full of corals and other marine life!
Today, the corals seem very well, and we saw many special sea anemones too.

The special find of the day was the Merten's carpet anemone (Stichodactyla mertensii) which Marcus first spotted. For a long while, we failed to find these anemones on our shores. But recently, we seem to be seeing them especially on our submerged reefs, often only one per reef.
The Merten's anemone, I realise, is kind of a combination of the Haddon's and Giant carpet anemones. The Merten's has the short stubby tentacles of the Haddon's, and the bright pink spots on the body column like the Giant. In the Merten's anemone, the body column is usually pale, while in the Giant this can be many other colours. That's what I notice so far.
The other special anemone find was made by James. It looks like the 'Neon' anemone that I've recently started seeing (Oops, no fact sheet on it yet). This one also has pink tips on its tentacles, but no neon stripes on the body column. James also got us a Reef wriggly star anemone which are very difficult to get a closer look at.
We also saw a nice Bubble tip anemones (Entacmea quadricolor), with nicely inflated bubbles on the tips of the tentacles.
There are lots of Magnificent anemone (Heteractis magnifica) here. Also many Giant sea anemones (Stichodactyla gigantea). Alas, none of us saw any clown anemonefishes today.
How nice to see the Pizza anemone (Cryptodendrum adhaesivum)! This sea anemone is usually well hidden, tucked deep in crevices, but this one was easy to photograph. This very flat sea anemone has a rounded thick edge so it looks like a crumpled pizza!
A little later on, I saw another Pizza anemone!
Alicia spotted the Snaky sea anemone (Macrodactyla doreensis)! But today I didn't see some of the special anemones I saw in the past like the Haekel's anemone (Actinostephanus haekeli) and Fire anemone (Actinodendron sp.).
As we had a full team today well spread out across the huge reef, I could focus on checking out what lives under dead corals and rocks. It can be quite colourful down there! Sponges, ascidians form bright artistic patches, dotted with snails, clams and all kinds of other animals.
One of the most intriguing finds under the stones were these tiny white Scintilla clams (Family Galeommatidae) that cover the shell with their brown body mantle.
When submerged, these tiny clams have little pointy bits sticking out of the body mantle that covers their shell. The clams jump around rapidly using a long white thing that sticks out of the shell (it's foot?). 
I saw this strange clam under one stone. I'm not sure what it is. There were also scallops, hammer oysters, tiny oysters and other strange clams.
Under one of the rocks was a large brittle star with very long arms (Ophiotrix longipeda) ! James saw an enormous Cushion star (Culcita novaeguineae)!
James also found this tiny red crab.
It was good to see that many of the species that were badly affected by coral bleaching such as the Anchor corals (Family Euphyllidae) were back on the reef. I saw several of these species. I also saw many nice colonies of Acropora corals (Acropora sp.).
I was very glad to see this colony of Moon coral (Diploastrea heliopora), which I think is the most elegant of our hard corals.
I saw a few bleaching coral colonies, and some of the Asparagus soft coral (Family Nephtheidae) were rather pale with yellowish rather than purple or brown tips. I noticed this during my brief trip here in May as well.
It was good to see rather longish Tape seagrass (Enhalus acoroides) among good growths of Spoon seagrass (Halophila ovalis). But the seagrass meadows here are still not as lush as they were in 2010.
Russel and Chay Hoon each spotted a Fluted giant clam (Tridacna squamosa). The team also saw several Tiger cowries, seahorses, bubble shell snail, nudis and more!

Oh dear, there were two huge fish traps on the reef edge. Each about 1m long. In one of them, there were four large Blue-spotted fantail rays (Taeniura lymma). I made a hole in the traps to release the animals.
A huge cuttlefish was in the trap! Thankfully, we managed to release all the fishes. This Terumbu seems to be one of the targets of fishermen. In 2011, we saw a large driftnet laid right across the reef, trapping many fishes.
There was also another spot which looks like a boat strike. A deep gouge in the reef where a boat probably ran aground. In it, another large trap. Fortunately empty. We disabled all the traps.
This amazing reef lies right next to Pulau Bukom, the location of massive petrochemical plants.
Here's a map of Terumbu Semakau.
Let's hope this marvellous reef survives the many pressures it faces.

Tomorrow, the last of the morning low tide trips for this series! With TeamSeagrass to Pulau Semakau!

Posts by others on this trip
  • Russel with three tiger cowries, corals and more.
  • James with awesome close ups of nems and more.


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