Monday, May 04, 2009

Exploring Pulau Jong - the Boat Island

This is quite a long overdue post. Didn't quite have the time to start writing it, due to the various guided walks I had last week, and I always give priority to blogging guided walks so that my participants will get to see it fast.

A few of us RMBR volunteers went to this little island, Pulau Jong, on 30 Apr. Pulau Jong, otherwise also known as the Junk Island, is located about 6km off the southern coast of Singapore.

Pulau Jong
I always thought it looks like a "pau", i.e. Chinese bun, from afar :P

We always pass by this island on our way to Pulau Semakau, but this was only my 3rd trip on it. Legend has it that a Chinese junk was attacked by Malay pirates one night at where the island is currently located, and as the pirates were about to board the junk, the captain woke up and on seeing them, gave such a loud scream that the sea spirit turned the whole junk into an island.

The sky was dark when we reached the island. As you can see, it is very near to Pulau Semakau behind. A thunder storm soon hit us, and RH, SY and I who got onto the island first had to hide in a little cave, while the rest waited on the boat.

The sky soon cleared after a while, and the rest also got onto the island on a little dinghy.

Toadstool Leather Coral (Sarcophyton sp.)
What I liked best about Pulau Jong was the lots and lots of pretty soft corals in the huge tidal pools! The above shows several colonies of Toadstool Leather Coral (Sarcophyton sp.). These soft corals have symbiotic algae (aka zooxanthellae) which photosynthesize and provide them with most of the nutrients they require, though they are filter feeders and can filter for plankton from the water too. Some of the species produce toxins which can be harmful to surrounding organisms, thus ensuring that they will have sufficient space for growth.

 Lobed Leather Coral (Lobophytum sp.)
There were many colonies of Lobed Leather Coral (Lobophytum sp.) too. Like the Toadstool Leather Coral, they too harbour zooxanthellae.

Dead Men's Fingers (probably Sinularia sp.)
The above are the Dead Men's Fingers (probably Sinularia sp., but some Lobophytum sp. could look very similar too). Imagine looking at these corals swaying with the waves - they will look just like fingers waving at you!

Branched Sea Anemone (Phymanthus sp.)
Related to the soft corals are the sea anemones, and we saw this pretty yellow Branched Sea Anemone (Phymanthus sp.) not too long after we started our exploration. Sea anemones have stinging tentacles to catch small animals.

And not too far away from the anemone was another stinging animal -jellyfish!

Maxima Giant Clam (Tridacna maxima)
We walked further out, and KS brought us to see a Maxima Giant Clam (Tridacna maxima) he saw during a previous trip.

Giant Top Shell (Trochus niloticus)
Talking about giants, we saw several Giant Top Shell (Trochus niloticus) at the rocky shore too. This huge shell is often collected for food in the neighbouring countries. The shell is also polished and made into buttons and jewellery.

Black-margined Nudibranchs (Glossodoris atromarginata)
Jong has always been a great place to find slugs. Despite the strong wind creating a lot of ripples, which made it really difficult to spot things, we still managed to find quite a few slugs, including 3 Black-margined Nudibranchs (Glossodoris atromarginata).

Pustulosed Phyllid Nudibranch (Phyllidiella pustulosa)
This is a Pustulosed Phyllid Nudibranch (Phyllidiella pustulosa). Slugs from this family are able to release powerful toxins into the surrounding water when they are stressed. They feed on sponges.

Dermatobranchus Nudibranch (Dermatobranchus sp.)
The Dermatobranchus Nudibranch (Dermatobranchus sp.) appears to be in season, and were every where! Nudibranchs from this genus usually feed on soft corals.

Sap-sucking Slugs (Order Sacoglossa)
We also found several small Sap-sucking Slugs (Order Sacoglossa), which we all had a hard time trying to take good photos of them since they were so tiny! These slugs are able to store the chloroplast from the sap that they have sucked from the algae, and use them for photosynthesis!

Thuridilla gracilis
Another sap-sucker I found was this Thuridilla gracilis.

Mosaic Crab (Lophozozymus pictor)
Several crabs were also spotted. This Mosaic Crab (Lophozozymus pictor) is the most poisonous crab in Singapore, and the toxins will not be destroyed even after you cooked it.

Spotted-belly Crab (Ozius guttatus)
A Spotted-belly Crab (Ozius guttatus) was hiding in a hole among the rocks when we found it.

Red-eyed Reef Crab (Eriphia ferox)
There were lots of Red-eyed Reef Crabs (Eriphia ferox) on the rocky shore, and they can be quite aggressive!

Black Sea Cucumber (Holothuria leucospilota)
Like other rocky shores in our other southern shores, there were quite a number of Black Sea Cucumbers (Holothuria leucospilota). This sea cucumber will eject sticky white threads from its backend when it is stressed, a defence mechanism to confuse its predator.

Stonefish Sea Cucumber (Actinopyga lecanora)
Another sea cucumber we saw was the Stonefish Sea Cucumber (Actinopyga lecanora). This sea cucumber is usually found among the coral rubble, and can really blend into the surrounding with its speckled pattern!

Soon, the tide was rising and we had to leave. This was again a really great trip, and I was glad that I was able to visit this little island again! :)


chris said...

I love seeing the stuff you find. The nudibranch photos are always great but it was nice to seeing the clam. Im a clam nut:)

Ron Yeo said...

Haha. I am more a sea star nut. But like clams and nudis too :)

Maximus said...

Very cool, I am so jealous of you to be able to go out and do this stuff.

neil said...

Fantastic set of crabs :)

great photos as ever

Ron Yeo said...

Nice to hear from you again, Neil :)