02 February 2010

Hard coral fix at Hantu

It's been quite a while since I've visited the reefier part of Hantu.
Wow, I've forgotten how stunning it can be!

We were out with Mei Lin for another Giant Clam hunt. Alas, the sargassum is still thick over much of the reefs. So we headed for a narrower stretch that wasn't so weedy.
The reef lies just across from the massive petrochemical plants on Pulau Bukom (we could hear the refinery whistle and whine all night like jet engines). But there are stunning reefs on Pulau Hantu!
Despite the rather murky water, all kinds of hard and soft corals crowd the shore. There were lots of the usual common Favid corals (Family Faviidae) in various colours and patterns.
Familiar Brain corals (Family Mussidae) were large and healthy looking.
While some colonies were stunningly large: like this Lettuce coral (Pavona sp.) with blades about 50cm long, that resembles the fins of a turbine.
While this Long mushroom coral (Family Fungiidae) was about the length of my entire arm! Really!
There were also other representatives of the mushroom corals: (clockwise from left) Heliofungia actiniformis, Circular mushroom coral, Long mushroom coral, Herpolitha sp.
There were several colonies of Anemone coral (Goniopora sp.). This one looks like the kind I commonly see on other shores.
But these look a little different. Hmmm...
I also saw many large colonies of Carnation corals (Pectinia sp.) in various colours and patterns. Not something I usually encounter on other shores.
Another hard coral in delightful abundance were Ridged plate corals (Merulina sp.), in various colours and some colonies were large. The ridges on these plate corals run from the centre to the edge.
I seldom see the Ringed plate coral (Pachyseris sp.) too! In this plate coral, the ridges resemble tree rings.
I saw strange forms of hard corals that are commonly seen elsewhere. This hard coral is a Pore coral (Porites sp.) from its tiny corallites. But the lollipop-like colony shape is not something I've often seen.
There were a lot of these little prickly ball-shaped colonies. They formed quite a large patch in deeper water.
A closer look and they turned out to be Galaxy coral (Galaxea sp.). These corals are quite aggressive and can put out long sweeper tentacles to get rid of annoying neighbours. Here's a closer look at these prickly animals. Each tiny polyp creates a star-shaped corallite.
In contrast, I only saw small, solitary colonies of this greenish Galaxy coral. Perhaps it's not as anti-social are the prickly ones?
Wow, Pebble corals (Astreopora sp.)! And many colonies too, some large.
These look similar to the more common Favid coral with tiny o-ring shaped corallites. Until you take a closer look at the corallites.
I was quite delighted to see large colonies of baby-blue branching Horn corals (Hydnophora sp.). I think the last time I saw them in Pulau Hantu was in 2004!
The unique feature of Hydnophora corals are the small conical mounds, called monticules (also hydnae or hydnophores), that form where the corallite walls of adjacent polyps fuse together. The monticules generally conical. The colony can also be encrusting.
I also saw several hard corals which puzzle me. This encrusting coral is quite intriguing. Possibly Montipora sp.?
And here's another one with a branching form.
I know this is an Acropora coral (Acropora sp.). Always nice to see a colony of this rather fragile coral.
As I was taking the photo, I noticed a bit of colour tucked deep among the branches. Could it be the Broad-barred acropora goby (Gobiodon histrio)? A study showed that this fish almost never leaves its coral home and stays despite low oxygen levels in the water and even when the coral is exposed at low tide. To do so, the fish is able to breathe air!
Well, I was terribly fixated on hard corals! And hardly saw anything else. Some of the other stuff I chanced upon was this corallimorph covered with tiny acoel flatworms.
A very large Spoon-pincer crab (Leptodius sp.) surprised me, and it seems every other team member that wandered by.
Pulau Hantu is one of the few shores where we can see large groups of Magnificent anemones (Heteractis magnifica).
I missed all but the most obvious slugs and slithery critters: A Glossodoris atromarginata (which Travis calls the Cream cheese nudi - a great name!), and the commonly seen Pseudobiceros uniarborensis.
I saw the strange Seagrass seahares (Phyllaplysia sp.) again! There were big ones, well, less small.
And really tiny ones too!
The rest of the team saw other wondrous stuff like a seahorse, lots of different nudis and flatworms doing strange things, other kinds of hard corals and more.

On the way home, I said farewell to the sole Burrowing giant clam (Tridacna crocea) we had found so far on Pulau Hantu.
Here's what it looked like at the beginning of the trip when it was still underwater, before the tide went out.
Too bad we couldn't find any other giant clams on the trip.

We had a glorious sunset over the reef. Alas, with huge equipment just off Pulau Hantu on the horizon.
At night, Pulau Bukom looks pretty, like a Christmas tree. But sounds and smells as you would expect a massive refinery to. The tang of hydrocarbons and clanging and whizzing were ever present throughout our trip. Nevertheless, marine life still thrives on Pulau Hantu.
Here's the rest of the team still exploring the lagoon under a rising moon.
Let's hope this miraculously marvellous shore remains for all to enjoy.

You can also dive at Pulau Hantu with the Hantu Bloggers! Check out the Hantu Blog for gorgeous underwater photos of our wild Hantu reefs, and find out more about how to join their dives.

Other posts about this trip
Singapore Nature by James

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