Sunday, April 26, 2009

Checking out Tanah Merah

Decided to visit a part of Tanah Merah shore which we have not visited before with LK and ST. While the beach was enclosed within a rock bund, there were still quite a number of interesting things to see!

Acorn Worms (Class Enteropneusta)
Acorn Worms (Class Enteropneusta) were quite abundant on the sandy shore here, and the above is the cast of one of them. They feed on tiny organic particles in the sand by swallowing the sand and process the edible bits. The remaining sand is push out of its backend, forming the coil of sand.

Boulder Hard Corals
Several small colonies of Boulder Hard Corals could be seen in the tidal pools here. Like most hard corals, we can usually only see the small coral animals (aka polyps) when the colony is underwater. The hard structure is made by the polyps with calcium carbonate. The tiny little dots you see on the coral above are the "doorways" to the individual "homes" of the polyps!

Horned Ghost Crab (Ocypode ceratophthalma)
We found this Horned Ghost Crab (Ocypode ceratophthalma) holding onto a fish, and the fish was still alive! This crab usually only come out at night, and while it does hunt for food, it is also a scavenger.

False Limpet (Siphonaria atra)
This flattish object stuck to the rock is actually a snail - a False Limpet (Siphonaria atra). While it is found on the shore area, it does not have gills and breathe with lungs instead. The flattened, shield-like shell allows it to hold tightly to the rocks and prevent it from being dislodged by the waves.

Have asked SK the ID for this snail before, but again, left it in office! Will have to check when I'm back and update later. In any case, was really glad to see one that was still alive - the last one I saw was just a dead shell. Update: This is a Trigonostoma scalariformis.

Clithon Nerites (Clithon oualaniensis)
This shore also has plenty of little Clithon Nerites (Clithon oualaniensis) with rounded shells, and somehow many of them stuck themselves to the plentiful creeper shells (probably Batillaria zonalis).

Angaria delphinus
This may appear to be a rock...

Angaria delphinus
But it is actually a snail! This is probably Angaria delphinus from the Family Trochidae. The other place which I have seen this was Semakau, but they are probably more common than that, just that being so well-camouflaged, most people tend to miss them.

Fan Worm (probably Sabellastarte indica)
Several pretty Fan Worms (probably Sabellastarte indica) were also found. They feed by collecting plankton or tiny organic particles in the water with their tentacles.

Sea anemone
Found this unknown sea anemone on the sandy shore.

It's always interesting to watch a flatworm sliding among the rocks and seaweed. Being so flat, it easily slides through tiny gaps, and is always so graceful while doing that!

Penaeid Prawn (Family Penaeidae)
This small Penaeid Prawn (Family Penaeidae) was being very cooperative and I had quite a few shots of it.

I have no idea what shrimp this is, but it sure looks pretty!

Halfbeak (Family Hemiramphidae)
The tidal pools were really great for taking photos of fishes, and we found many of which we couldn't identify. The above is a halfbeak (Family Hemiramphidae), but I have no idea of the exact species.

White-spotted Rabbitfish (Siganus canaliculatus)
Several juvenile White-spotted Rabbitfish (Siganus canaliculatus) were seen hiding under seaweed and near rocks. This fish is very popular during Chinese New Year, as it coincides with the fish's breeding season and the roe is considered a delicacy by many Chinese.

Striped Eeltail Catfish (Plotosus lineatus)
One huge school of Striped Eeltail Catfish (Plotosus lineatus) were swimming around the tidal pool, forming interesting formations along the way. This fish has a venomous spine on its dorsal fin, and one on each of the pectoral fins too, which can sting very painfully.

Flower Crab (Portunus pelagicus)
A little Flower Crab (Portunus pelagicus) was found among the pebbles and snails. This crab can swim very well with its paddle-like back legs.

Blue hermit crabs
LK found these little blue hermit crabs clinging onto a piece of rope. Have no idea what species they are. (Update: these are Clibanarius merguiensis. Thanks to Yoyo for the ID!) The only other blue hermit crab I have seen are the Blue-striped Hermit Crabs (Clibanarius longitarsus) usually found in or near mangroves, but these do not have stripes, and the colours of the eyestalk and antenna are different too.

White-spotted Reef Hermit Crab (Dardanus megistos)
A pleasant surprise will be this White-spotted Reef Hermit Crab (Dardanus megistos). This hermit crab is more commonly seen on coral reefs.

Land Hermit Crab (Coenobita sp.)
On my way back out of the shore area, I saw several Land Hermit Crabs (Coenobita sp.), but unfortunately they're all really camera-shy.

On a whole, this was a really good trip, and I do hope to find time to come back again!

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