30 March 2009

Return to Terumbu Raya

Another glorious sunrise trip, to the Great Reef: Terumbu Raya.
We were back on this submerged reef off Pulau Semakau. Among the intrepid explorers was a team of students from ITE led by their valiant teacher Cecilia. They are planning to do a documentary about marine conservation in Singapore!

As Melvin was finding the best spot to land, Kok Sheng and I can't resist taking more photos of the spectacular sunrise over Pulau Semakau.We are greeted by several Blue-spotted fantail rays (Taeniura lymma).
The size of coffee saucers, these small fishes zip away into the reefs as we gently find sandy spots to step on. These sting rays are often seen on our Southern reefs.Some parts of Terumbu Raya have fabulous encrustations of hard corals.Large colonies growing close to one another.

There were also good sized colonies of some of the rarer hard corals.There was a large Ringed plate coral (Pachyseris sp.), which form a plate-like colony with fine ridges in rings.Another plate-like coral that I don't see very often is this Ridged plate coral (Merulina sp.). This coral has 'walls' that form meandering valleys and ridges, radiating from the centre of the plate to the edges. It comes in pretty colours and this one was maroon with little pale blue 'eyes'.
The Carnation coral (Pectinia sp.) is not often seen. But many nice colonies were seen at Terumbu Raya.
It's always nice to see Acropora corals (Acropora sp.). However, these are not as plentiful at Terumbu Raya, as in undisturbed reefs like Raffles Lighthouse.Cauliflower corals (Pocillopora sp.) are also branching corals, and are commonly seen on many of our reefs. When the tiny polyps are expanded though, the colony appears fuzzy and I suppose does resemble cauliflower.Another branching hard coral that is hard to distinguish with all the polyps extended is Branching anchor corals (Euphyllia paraancora). The tentacles have U-shaped tips and expand like a chrysanthemum! This hard coral is not that commonly seen on our reefs.
Galaxy corals (Galaxea sp.) are quite regularly seen on some of our better reefs. These have pretty polyps with white tipped tentacles.This seems to be a different kind of Galaxy coral.It was also nice to come across several Tongue mushroom corals (Herpolitha sp.). These hard corals are not attached to the surface as adults.

I also saw lots of Favid hard corals (Family Faviidae), as well as many colonies of Brain corals (Family Mussidae) and Anemone corals (Goniopora sp.) I came across one colony of Lettuce corals (Pavona sp.).

The reefs form the basis for a community of all kinds of animals. Among the living corals were other animals such as fan worms, sponges, ascidians and sea anemones.
I came across one large Bubble tip sea anemone (Entacmea quadricolor) but it had no resident anemonefish.

A little further along, I came across a small Giant sea anemone (Stichodactyla gigantea),with a really REALLY tiny False clown anemonefish (Amphiprion ocellaris)!
There were also lots of different kinds of Frilly sea anemones (Phymanthus sp.). Kok Sheng also saw some special sea anemones such as the Fire anemone (Actinodendron sp.) and a very colourful Pizza anemone (Cryptodendrum adhaesivum), as well as a Wriggly star anemone. See his blog for the lovely photos.
Nestled among the coral rubble was also this small Long-spined black sea urchin (Diadema sp.). These sea urchins seem rather seasonal. At times we see lots of them on the intertidal reef flats, and then none at all. Is the Diadema season starting up?

Chay Hoon also found a Red feather star and Kok Sheng saw the White-rumped sea cucumber (Actinopyg lecanora). Other than those, we didn't see any other echinoderms. Despite looking, we failed to find any Knobbly sea stars (Protoreaster nodosus).

Of course Kok Sheng and Chay Hoon find lots of special nudibranchs and one special flatworm! I failed to find any.

Other creatures I failed to find despite tantalizing signs include:Cone snails: these fascinating animals have toxins so powerful that some can kill people. I saw some cone snails shells and hoped to see a live one. Alas, none were encountered.There were also several empty half-shells of what seems to be small Burrowing giant clams (Tridacna crocea). Again, I failed to find any living ones.

Unfortunately, I did find a large abandoned driftnet draped across the reef flat.
In the background are Pulau Hantu (the green island on the left) and Pulau Bukom (the industrial installations on the right).

The tide turned very soon and it was time to go home. Terumbu Raya is certainly worth another visit as it's way too large to explore completely in one trip.

Other blog posts about this trip

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