Jul 4, 2007

Jong: Life amidst Industry

Another dawn and wildfilms were at Pulau Jong, which lies just off Pulau Bukom (seen in the background).
At high tide, all that can be seen is the dome-shaped forest-cloaked islet with striking natural cliffs. Jong then looks somewhat like a dumpling!

At low tide, a vast intertidal area is exposed. This area is long and narrow, so together with the 'dumpling' the entire island looks a bit like a large Chinese sailing junk. Which is how the island is believed to have gotten its name.

This tiny island lies across the city centre, right next to busy, major shipping lanes where large ocean-going vessels ply.Right next to Jong is Pulau Sebarok, which is basically the petrol station of our harbour, hosting bunkering services and supplies. (There was a constant smell of benzene on Jong) The vast landfill on Pulau Saking and Pulau Semakau are on the other side of Jong. The white building in the background is the marine transfer station on Pulau Saking where all our incinerated waste is transferred twice a day.
Jong is also adjacent to Pulau Bukom, where major petrochemical plants are located.

Despite being literally surrounded by busy shipping and heavy industries, Pulau Jong is clearly very much alive!The lagoon near the cliffs teem with leathery corals.

Like hard corals, these are colonial animals. Each colony is made up of polyps that look like tiny sea anemones. These polyps have 8 tentacles that are branched (while most hard corals have 6 or multiples of 6 tentacles that are NOT branched). The polyps share a leathery common tissue instead of building hard skeletons like hard corals do. At low tide, when the colony is exposed, the polyps are retracted so all we see is the leathery tissue.

The colonies come in a bewildering variety of shapes and colours. Some look like fried eggs, others like surgical gloves. Leathery corals are identified by (among other things) the kind of polyps they have. Here's a look at some of the polyps of various colonies.

Some have polyps with short body columns.
Others have polyps with long body columns.
There were also lots of hard corals on the reef flats, including some rarely seen elsewhere.

This is probably Hydnophora sp, a hard coral with little cone-shaped parts on their skeleton.
This one may be Merulina sp., a plate-like hard coral with meandering valleys.And the always delightful Acropora hard corals, often with little animals hiding among their branches.
My most exciting encounter was with this beautiful hard coral. I've only seen it one other time on Sisters Island. It is possibly Diplosastrea sp.
The reef was also alive with animals. A little flatworm with delicate bars crawled quickly away.
An unusually large number of the frilly Glossodoris atromarginata nudibranch was seen. I saw four. We really don't know why.

Ron came across this strange conch snail. It was way too big to be the other kinds of small conch snails that we usually see. Fortunately Dr Tan Koh Siang was with us and he told us it is a juvenile Spider conch (Lambis lambis) which hadn't grown its spines yet. Amazing! We learn something new everytime we visit the shores!

Ron saw lots of other amazing things too, like a cushion star, various nudibranchs and sea cucumbers. Check out his tidechaser blog for all the photos and stories.

And just before we had to leave, I came across these two cute and happy little fishes!
The island was also visited by a pair of Great-billed herons, and a pair of juvenile White-bellied fish eagles. Ron, Chay Hoon and Alvin also spotted lots of other things. I'm sure Ron will blog all about it soon.

Pulau Jong is an example of what an untouched island can be, even if it is located in the middle of industrial activity.


Jeffrey said...

Hi, the identities of the hard corals looks right.

Cheers, Jeff :)

Ria Tan said...

Thanks Jeff!

I feel very inadequate about putting ids to them.

But they are gorgeous animals and I can't help taking pictures of them and posting about them.