11 April 2012

Shark! At Terumbu Hantu

'Shark!' Sam exclaims as a Black-tipped reef shark swam in the shallow waters, probably hunting fishes. It swam right by me and my camera jammed! Sigh.
We also saw lots of special sea anemones and other strange creatures on our first time visiting this submerged reef off Pulau Hantu.

Terumbu Hantu is one of the last few small submerged reefs that we have yet to visit. It lies very close to Pulau Hantu. It is tiny, compared to the huge Terumbu Pempang Darat we visited two days ago.
Visiting Terumbu Hantu reminds me of Terumbu Bayan, which was reclaimed in 2006 to expand the refinery facilities on Pulau Bukom. This 2003 Google Earth image shows where Terumbu Bayan used to be.
We arrive a little early and the tide is still rather high. But as usual, this didn't stop the intrepid team.
Soon enough, the tide fell and we could have a better look at this submerged reef. It has all the usual kinds of leathery soft corals. On the horizon, the artificial seawall on Pulau Hantu and the refineries on Pulau Bukom.
Here's a view of the reef facing the Life Firing Islands on the horizon.
Although there wasn't any area thick with corals, unlike the shores on Pulau Hantu itself, there were many different kinds of corals on this submerged reef.
Today was a sea anemone day for me! I saw this intriguing colourful sea anemone that I seldom come across. It had red tipped green tentacles and neon green patches on its body column. Alas, it was deeply embedded in a crevice. Fortunately, later on, Jose found one that was stuck under a big piece of coral rubble.
It was much easier to take a closer look at Jose's sea anemone! It had neon green stripes down the body column, bumps around the oral disk and a bit underneath near the edge. The tentacles many, thin and green. I have no idea what it is! Hopefully, with this closer look, we can find out what it is!
Hmm...I wonder if this is the rather rarely seen Merten's carpet anemone (Stichodactyla mertensii).
It  had a tiny Clown anemonefish (Amphiprion ocellaris) in it!
This sea anemone had really large pink bumps, but which don't really go all the way down the body column. It had short as long tentacles with rather bulbous tips.
There were also the usual Giant sea anemones (Stichodactyla gigantea), which also has pink spots on the body column but is less violently pink. Hmmm ... it's tough to differentiate these similar looking sea anemones. All the sea anemones I saw had anemonefishes in them, though very shy ones. Russel found a large Bubble tip sea anemone (Entacmea quadricolor) with a fierce Tomato anemonefish (Amphiprion frenatus) in it.
I also saw these things. I'm not too sure what they are. They retracted deep into crevices, so they are probably not corallimorphs or hard corals. Another strange sea anemone?
How nice to come across several clumps of these Xenia soft corals (Heterozenia sp.). I first saw these animals on Terumbu Bayan! It was only much later that I saw them again on our other submerged reefs.
These are not sea anemones. Each clump of soft coral is a colony made up of tall polyps with branched tentacles. In between the tall polyps are flower-like secondary polyps of the colony.
Finally, we figured out who has been laying the bright orange strings of eggs that we often see on the reefs! When we turned over this Spider conch (Lambis lambis) to take a look at it, we noticed the bunch of eggs nearby.
Russel noticed an egg string coming out of the snail! Below is also a closer look at the pile of egg strings and the eggs. We carefully replaced Mama Spider conch so she could continue her laying.
Oh dear. Sam found a large Fluted giant clam (Tridacna squamosa) that looked like it died on the reef. We didn't find any living giant clams on the reef today.
Under a piece of coral rubble I noticed this clam wedged in a little hole. I don't know what it is.
I saw this very spotty Jorunna nudibranch. I wonder if it's just a super adorned Jorunna funebris or something else?
The fine black patterns on the nudibranch is not just pigment but actually black prickles on the animal. The striking black-and-white pattern is probably some kind of warning that the nudibranch is not nice to eat. Do the prickles have anything to do with this? I have no idea!
Russel and I both found this little smooth orange sea cucumber. Mine had dark spots, but Russel's was plain orange. Russel reminded me that Kok Sheng also found one of these on Pulau Hantu itself. These sea cucumbers were stuck on top of coral rubble. We don't know what it is yet.
The sea cucumber like to stick its mouth to a hard surface, while sticking out its bushy tentacles one at a time against the surface. I wonder if this is how it feeds? Sam and Jose each found a different Cushion sea star (Culcita novaeguineae)!
Under rubble, I found this tiny animal. At first I thought it was a chiton. But then it moved quite rapidly.
And this is what it looks like underneath, doesn't seem to have a 'foot' like chitons do. I have no idea what it is! Some kind of scale worm?
Under rubble too, a tiny little red crab. Another mystery!
There are also all kinds of colourful sponges here. As well as different kinds of seaweeds and the usual variety of common marine life seen on our submerged reefs.
There's some clumps of Tape seagrass (Enhalus acoroides) and they all seem rather long and none were bleaching. I didn't come across any other kind of seagrass.
We noticed a raptor hovering over the reef at low tide. Was it hunting for fishes, just like the shark? (I feel really bad missing the shark shot...I'm more used to taking photos of slow-moving animals. Very sorry Sam!).
Today, we saw many large Carpet eel-blennies (Congrogadus subducens). Some were bluish, others greenish or brown. I'm sure these would make a tasty meal for the eagle.
We could see a huge fish trap ('bubu') even before we landed. But when we got closer we were relieved to find that it was already broken. It's a pity that fish traps continue to be laid in the middle of such rich reefs.
The weather was highly variable, and approaching lightning almost made us leave. But we stayed on until the tide turned. What a great trip on a nice little reef!

MORE trips ahead as the low spring tides continue. It's an exhausting schedule of predawn trips but there's no other way to get a brief glimpse of these marine marvels!

Posts by others on this trip
  • Sam with lots of colourful corals and cushion star!
  • Russel with amazing underwater shots, sea anemones and more. 
  • Jose with more sightings.


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