Nature: A Photo Montage reminiscing Pulau Semakau

Hi all,

This is a continuation of the previous Pulau Semakau posts. It is a collection of photos taken there some time back. Beneath the dull and deceivingly lifeless facade, it is actually home to more than what the mind can picture. Enjoy!

This little critter here is a fiddler crab, and is a male, no prizes for guessing correctly. Its right claw is rather large and brightly coloured, but not quite as beautiful as that of some other fiddler crabs which I had seen before. Some of such crabs are home at the beaches of Pasir Ris park. This crustacean here was scurrying along on the mud near some mangrove trees. Fiddler crabs are more terrestrial than aquatic when fully grown but cannot climb well, unlike their mangrove companions, the vinegar crabs.

First picture from the top : A fiddler crab, barely outside its burrow, prepares to scuttle back to safety should there be any imminent danger.

Second picture from the top: A close-up picture of a fiddler crab, showing the stalked eyes and the predominantly larger right claw.

Here is an upside-down jellyfish, which the guide scooped up from the water into a plastic container and released back into the mudflats later. It is quite cute, appears soft, is a not-very-vibrant brown and white, has a very mild sting and sucked and pushed water in and out of its bell furiously (in a rather fruitless attempt to move) when confined in the container. It camouflages quite well in its natural environment, as seen in the above picture.

Do you think that the mudflats are home to only shells and crabs? In reality, the answer is no, of course not! The biodiversity in mudflats is quite rich, and the people who are in charge of catching or pointing out interesting animals (which they caught or found) to the visitors managed to capture this snapping shrimp. Is it not obvious why the snapping shrimp obtained its name? It is just called so because it makes snapping noises! These noises the snapping shrimp makes using its enlarged claw which is specially meant for that purpose. A snap from that claw creates enough pressure to kill small fish and can create a loud clicking noise. I heard much of those clicking later on in the walk, but I could not find any shrimp. Those invertebrates were probably snapping away in the luxury of their burrows, which were difficult to find in the muddy waters. Immediately after this shrimp slightly longer than my middle finger was released, it disappeared into the seagrass and muddy water in less than two seconds.

First picture from the top: A species of snapping shrimp that resides in the mudflats. Note the noticeably larger snapping claw.

Second picture from the top: Some seagrass and a little snail atop it. This particular species of snapping shrimp hides amidst the seagrass.

I am sure that all of you know this organism. To the Chinese, it is a delicacy, one of the "山珍海 味" that is eaten during the Chinese New Year. This is one of the several species of sea cucumber, known as the ocellated sea cucumber or the eye-spotted sea cucumber. (Yes, it is harvested for food.) Compared with the other fauna I mentioned earlier, this one is a "colossus", being slightly shorter than the length of my entire forearm and hand. Obviously, this lazy creature did not need to be caught, for it was too large and too slow, rendering the small plastic container obsolete. This sea cucumber, like many others of its species, is somewhat soft, but has a bumpy texture. It squirmed (though very slowly) a little at the foreign stroking of its skin by many fascinated visitors and made no move to defend itself.

I suppose all of you recognize this animal. It falls under the class of brainless echinoderms (literally!) and it is none other than the common starfish, more accurately called the common sea star. Not all starfishes are vibrant and colourful, and this starfish that is a resident of mudflats is such an example. On noticing a starfish atop the mud, I was very excited-that is, until I discovered that there were tonnes (metaphorically) more of them lying hidden beneath or half-buried in the mud. Many of them were seemingly mating, and there were numerous pairs of sea stars, with one above the other. As sea stars undergo external fertilization, they do not actually mate but just release their eggs and sperm into the water. Starfish use sea water to substitute their blood, and thus I learnt that it was very stressful when they are taken out of the water, for they would not be able to move if so. Unfortunately I learnt that only after the trip. Luckily I placed the starfish back to their original position after touching them.

Second picture from the top: A starfish turned upside down. Note the small tube feet sticking out of the grooves in the middle of the arms.

First and second picture from the bottom: Two sea stars "mating".

The above pictures show a type of gastropod, which is a family that includes slugs and snails. It falls under the class of molluscs. This organism is either a marine flatworm, a nudibranch or a sea hare, all of which are less commonly known invertebrates. I do not think that it is a flatworm, for I feel that flatworms should be flatter than this and be more oval in shape. This gastropod could possibly be a sea hare, but sea hares appear to be of a different colour and much "hairier". There is also a possibility that it might be a nudibranch. Being unfamiliar with these types of molluscs, I am not too sure of this creature's identity. However, I can remember that it was placed into a plastic container for our convenience in observation and photo taking.

This organism, as all of you can tell too easily, is a shell. But what type of shell exactly is it? This shell, according to the Pulau Semakau brochure, is a noble volute. A noble volute is no small shell that you can easily pick up and bring home without arousing suspicion from anyone, but is a fairly large mollusc that is several centimeters longer than my entire hand. Usually, noble volutes do not appear especially beautiful or attractive as they are covered in mud, algae, etc., or rather basically anything which can help to camouflage them from us horrible humans (no offense to any homo sapien who is reading this, ha ha!). Scrape away the grime and dirt on the outside, and there lies the true appearance of the noble volute: a beautiful marbled pattern that makes you feel like smuggling it home. And what may be the identity of the peculiar clump of translucent whitish objects beside the shell? Well, those are eggs of the parent noble volute! Surprised? I never thought that such large and weird looking eggs could belong to this shell too. I actually thought that they were some type of odd plant at the first glance...

First, third and fourth picture from the top: A parent noble volute lies with its eggs. Note how large the eggs are in comparison to its parents.

Second and third picture from the top: The noble volute actually has beautiful brown markings on its green shell that greatly resemble marble.

In a plastic container, our group finds a scallop. Scallops are bivalves and can be much more beautiful than this. They can be a bright orange in colour, as proven from the specimens which my brother and I collected a long time back. This scallop was stubbornly immobile, like many other types of shells, although it can move quite quickly, relatively speaking.

We also found this heart cockle in the waters. Not taking its size into consideration, it is quite noticeable, judging by its unique shape and colouration. It really resembles a heart very well, and is a rather delightful shell. It can easily fit into my palm. I never knew about this species of mollusc before I went for the intertidal walk.

This small gastropod, probably a marine flatworm for it has no external gills, was found crawling along on the mud underwater. Marine flatworms are generally faster than nudibranchs and have no external gills. Only a handful of flatworms are not parasites and are free-living. What a pity, for marine flatworms are quite colourful and interesting molluscs.

I think that you should know what this organism is, but unfortunately the photographs aren't exactly of the best quality, so, my apologies. You might raise your eyebrows in disbelief, but this really is a cuttlefish. It was a small juvenile around the length of my middle finger, and was placed in a pail. Cuttlefish really are great colour-changers, and this one displayed its skill right before my eyes by turning into a much darker hue in less than three seconds when I put my hand inside the water. The cuttlefish, petrified at this "mysterious-alien-which-appeared-from-the-sky", let out several small jets of ink, which slightly darkened the water.

Good-quality pictures at last! The first picture depicts some soft corals. Soft corals grow much faster than hard corals as they lack an exoskeleton. Most of the corals you see in aquariums or brochure pictures about the Great Barrier Reef are hard corals. The hard coral in the second picture is a brain coral.

And walking on, our group discovered several knobbly starfish, large reddish-pinkish sea stars that are the mascots of Chek Jawa. They were rather heavy, being several kilograms in weight and from arm tip to arm tip measured over 30cm.

And so I shall end this photo montage with the icon of the mudflats. See you until my next post!