21 December 2010

Seahorse on oil-slicked Tanah Merah!

This beautiful seahorse is so well camouflaged among the Sargassum seaweed!
I saw him on oil-slicked Tanah Merah today!

Here's a clearer (sort of) view of the seahorse. Unlike the Estuarine seahorse (Hippocampus kuda) I saw on the same shore in October, I think this one is the Tiger-tailed seahorse (Hippocampus comes)! It looks rather young.
Here's a video clip of the lively seahorse. See how it uses its tail to 'jump' off. I never noticed this behaviour before. Today, I had the pleasure of Dr David Lane's company for the trip. Dr Lane is an expert in, among many other things, echinoderms. He is the author of the BP guidebook "A Guide to Sea Stars and other Echinoderms of Singapore". Dr Lane manages to take great shots of the beautiful fish!

Another less happy encounter is with Mr Stonefish. The Hollow-cheeked stonefish (Synanceia horrida) used to be and appears to still be quite common on this shore. Today, Mr Stonefish is half buried in the sand with his eyes and frowning mouth, and the business end of his spines sticking out, ready for the unsuspecting foot.
There were lots of fishes zooming about in the water. Most were too quick for sneaky swimming camera. But these tiny Chequered cardinalfish (Apogon margaritophorus) stayed quite still for a while.
Dr Lane found a Haddon's carpet anemone (Stichodactyla haddoni) with TWO anemone shrimps (Periclimenes brevicarpalis). In previous trips I usually only saw one anemone shrimp. Mr Shrimp is smaller, more transparent with fewer white spots, while Mrs Shrimp is fatter and has more white spots.
Here's a video clip of the shrimps in their anemone home. How remarkable to find such creatures on a reclaimed shore! And one that had been affected by an oil spill too.

Another special crusty find for me was this special hermit crab! I saw it once at Tanah Merah before the oil spill. This hermit crab has been kindly identified by liwaliw as Clibanarius cruentatus.
Dr Lane found a medium-sized Stone crab (Myomenippe hardwicki) under a basket! There were many tiny Tidal hermit crabs (Diogenes sp.) and a few Striped hermit crabs (Clibanarius sp.) and most of them were rather small. There were many tiny swimming crabs (Family Portunidae) in the water, most were Flower crabs (Portunus pelagicus).
I was glad to be able to show Dr Lane some Common sea stars (Archaster typicus). There were quite a few of them on the shore, I saw at least 10 of them and they were of a good size, seemed unharmed without any injured body parts, and quite active especially near sunset.
Dr Lane showed me the tiny parasitic snail (possibly of the Family Eulimidae) that lives on the poor Common sea star. The snail actually sucks up the sea star's body fluids. Oh dear. This is why, Dr Lane explains, many sea stars have tiny pinching structures on their body surface to get rid of such annoying beasts.
Dr Lane shows me some flatworms that he found under a rock!
A closer look at the flatworm. Wow, it's very pretty. I have not seen anything like this before. They were clusted on the beige colonial ascidians found under the rock, eating them?
I saw many happy fanworms (Family Sabellidae), both the brown banded ones and the orange ones.
It was a relief to see signs of several Acorn worms (Class Enteropneusta) on various parts of the shore. The coils of 'processed' sand are clean! There were also many busy shorebirds foraging on the shore.
I saw one living Black-lipped conch (Strombus urceus) and many young Gong-gong (Strombus turturella) which have yet to develop the thick 'lips' on the shell. On the rocky areas, Dr Lane found a strange pretty limpet.
Dr Lane spotted several living Fan clams (Family Pinnidae), and I saw a few clams on the rocks which were very much alive. I think the two on the lower row might be Thorny oysters (Spondylus sp.).
The hard corals were still seen on the shore, most look alright although some were producing mucus. I saw one small hard coral that might be a young Circular mushroom corals (Family Fungiidae), and another small colony that might be some kind of Disk coral (Turbinaria sp.). Zebra corals (Oulastrea crispata) remain quite common on the seawalls.
The most common hard coral on this shore were Favid corals (Family Faviidae).
There were also many Pore corals (Porites sp.).. Most seemed alright.
I saw one small Frilly sea anemone (Phymanthus sp.) , and one large colony of Button zoanthids (Zoanthus sp.).
We also checked on the patches of Smooth ribbon seagrass (Cymodocea rotundata) here. They seemed alright and I get the sense that the area they are covering is actually expanding.
Among this seagrass patch, the small Haddon's carpet anemones that I saw on my previous trip were still there.
The big patch of Tape seagrass (Enhalus acoroides) seems fine. Although the blades seemed rather chomped, they were clear of scummy stuff. I saw another small patch further away. I looked and looked and failed to find the patch of Sickle seagrass (Thalassia hemprichii) that was seen in the past. I fear it is gone. I also didn't see any Spoon seagrass (Halophila ovalis).
The most abundant seaweed on the shore remains Mermaid's fan (Padina sp.), with a few clumps of short strands of Sargassum seaweed (Sargassum sp.). I also saw one large clump of Codium seaweed (Codium sp.).
The shore seems to have been affected by erosion recently. A large Rhu tree has fallen over onto the shore.
Throughout our trip, these three people armed with a push net, a large hand net and plastic bags were wandering up and down the shore trying to catch fishes. They didn't seem to have much success.
There is still crude on the low water mark, leading to sheen on the water surface everywhere. In some parts, crude lies beneath a soft thin layer of sand. When I step on it, the crude comes 'twinkling' out. Here's a video clip of the effect.

Today I didn't see many large areas of scum, not the green, white or brown kind. There was some sheen on the water, but not a lot. This Tanah Merah lagoon seems less slicked that the other one nearer the Changi Naval Base.

Despite the wet start at the trip, the weather held and Dr Lane and I had a good trip. Dr Lane is impressed that an artificial shore still has such interesting marine life despite the oil spill. Let's hope the shore will recover soon!

More about the oil spill on this blog and on the Oil spill facebook page.

Later this evening, I'll be checking up on a Changi shore that we have not visited for some time.

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