Thursday, July 19, 2007

Intertidals @ Tioman

Finally back from Tioman after a week of field studies at the intertidal zone which my group has chosen to do on. Thought I would just share with everyone a different intertidal life from Singapore.

The intertidal group hard at work

Some of the interesting crabbies we found:

Spider crab

There were many small swimming crabs around. These crabs are characterized by their paddle feet at their last pair of legs.

An exciting find by Ngan Kee, a sponge crab. These crabs have their last pair of legs bend upwards which are used to hold a piece of live sponge over them. The sponge will continue to grow and the crab will trim them to fit nicely for cover.

Red eyed reef crab

A porcelain crab. These crabs are more closely related to hermit crabs than the true crabs, they have only 3 pairs of legs (1 pair not visible in this photo). Update >> Will be more correct to say they only have 3 pairs of walking legs, as apparently porcelain crabs have their last pair of legs hidden under the carapace.

A pregnant xanthid crab holding its eggs using her abdomen. This is why female crabs have a wider abdomen.

A view of coral life visible from low tide.

Besides crabs, there were also an abundance of snapping shrimps, long-clawed shrimps and many other prawns around, many which were too small to take a photo.

And now for some fascinating molluscs:
Ngan Kee found a two cone shells and they are alive! Finally had the chance to see one! Cones are famous for their venomous harpoon, a modified radula used to stun their prey. The venom can be fatal even to humans and there is no anti-venom

We brought back the cone to present to other students later, giving me the chance to take some macro picts to see if I can zoom in on the harpoon. Pity though, cant seem to locate it.

I was particularly excited about the number of cowries we saw, especially the bigger ones. This unknown cowrie (left) is about 10cm long. Cyroea arabica, about the same size as the other one.

Possibly a wandering cowrie

Here we can see the mantle of the cowrie covering its outer surface of the shell, making the shell having a smooth and glossy appearance.

The same cowrie (left), with its shell exposed. Another different cowrie possibly a Cypraea annulus (right).

We also found about 2 species of nudibranchs... Possibly a Discodoris lilacina on the right.

Spider conch. Lat shared with us this urban legend that each spine of the shell actually points to another spider conch.

Here was our guardian angel, a white cat which followed us throughout the entire transect. Before this, there was this guy who claims that he is researching on cats in predicting tsunami and warns us that there might be one approaching. We are doubtful of it and still carried on our transect but still, glad of the cat's accompany; just in case.

And there were the flatworms, also saw them alot of times~

and the long ribbonworms...

Giant clam with its symbiotic algae at the mantle

The Echinoderms

The most diverse invertebrate we saw were the sea cucumbers. About 7 morpho species found.

Holothuria hilla, the most abundant cucumber here. Almost every tide pool contains one.

Holothuria atra or lolly fish sea cucumber. Interestingly, it covers its dorsal surface with sand leaving only 2 longitudinal rows of circles of black.

Bohadschia marmorata. This is a sensitive species that eviscerates almost immediately when disturbed. I'm the guilty one responsible for accidentally stepping on the one above... A negative demonstration of cos.

Another unidentified cucumber.

There were many sea urchins at the far end of the reef flat which we saw while snorkelling. Diadema sp (left). Another different species with shorter spines.

Cute little starfishes found all over the rocks at the northern side of the Paya beach shore



Scorpionfish lying calmly in the sandy while all of us were taking shots at it.

Look at all these colorful reef fishes!

Spotted this wasp hive while strolling alone at the beach

Lastly was this "X-ray" pict of a dead mosy killed by Kaiyuan. We were tramatized by them every night and had to cover every part of our body to prevent being bitten.

In all, a pretty rewarding trip, but regrettably we had no time to venture into the freshwater stream and forest. Diving wasn't that much fun for the amount of money I paid. But had my first experience in night snorkelling, which was pretty exciting, seeing a large porcupinefish and stingray.

Thanx Ron, for the various IDs and corrections =)


Anonymous said...

hi, which part of tioman is this?
so interesting :)

Siyang said...

Hi, that was at Paya Beach Resort~

Anonymous said...

oh i see... Thanks!
You've made the resort more interesting by posting all this up.
Another interesting stuff we can do there ;)

Siyang said...

You planning for a trip there? If so, you would have to check the tide table for that place to see if there is a suitable low tide period.

Anonymous said...

oh really?
I thought it's just every night low tide is able to see those creatures.
Which month you went for this trip?

Siyang said...

There are a few days in each month whereby the tide goes low enough for a intertidal walk.

I found a tide table online for tioman But this only gives a predicted 7 day forecast. A sea level of below 0.5m would be good enough for a walk. You might want to consider calling the resort to find a further forecast.

Anonymous said...

wow! a thousand thanks man!
I'll do my homework to call them and check! ;)
I never knew there's such thing as intertidal walk till i found your post, which is actually good for us who don't have any diving license and yet we get to see it!

Many Many Many Thanks :)

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