Tuesday, December 16, 2008

Fishy business on Siloso

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Among the most obvious inhabitants that I found living in the murky swimming lagoons of Siloso Beach were various fishes. And although most of them refused to pose for photographs, I did manage to glimpse some of them for long enough to identify them tentatively.

The gobies were well-represented, with small groups of ornate lagoon-gobies (Istigobius ornatus) and shadow goby (Acentrogobius nebulosus) hiding on the seabed close to the rocks, and small mudskippers (Periophthalmus sp.) along the shoreline and amongst the rocks.

The rocks were a hiding place for more than just gobies, and I spotted a couple of orbicular cardinalfish (Sphaeramia orbicularis).

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I tried my best to stay still, and took these photos before they vanished. The murky water was a real challenge.

Close to shore, my movement disturbed schools of small fish, most of which darted away the moment the light from my torch fell upon them. Some of those that I recognised include Kops' glass perchlet (Ambassis kopsii), and juvenile deepbody mojarra (Gerres abbreviatus) and slender mojarra (Gerres oyena). I also managed to encounter a few tropical silversides (Atherinomorus duodecimalis), though not in large numbers like on other shores. In the deeper parts of the lagoon, occasional loud splashes hinted at the presence of much larger fish.

Among the sargassum (Sargassum sp.) that grows around the bridge that connects this islet to Siloso Beach, I made another exciting discovery.

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Two baby silver moonies (Monodactylus argenteus), only the size of my thumbnail. Aren't they cute?


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There were more schools of unidentifiable tiny fish hanging around the bridge and amongst the seaweed. Above a small bed of spoon seagrass (Halophila ovalis), I found a school of chequered cardinalfish (Apogon margaritophorus), which proved impossible to photograph, as well as young individuals of two different species of halfbeak (F. Hemirhamphidae). The identity of these two species is not known, but for now, Ria has labeled them as the 'twig-like halfbeak' and the 'broad-nose halfbeak'.

Two Bangladeshis crossed the bridge, carrying a large bag. One of them took out a cast net and waited at the water's edge. There was a splash, and as if on cue, he deftly threw the net into the water, waited for it to sink to the bottom, then slowly hauled it to shore. As the two men dragged the net up onto the beach, there were sudden tiny flashes of blue light, made by the tiny crustaceans known as ostracods or mussel shrimp.

I wasn't surprised that they managed to catch fish, but I was really surprised at the size of the fish they caught!

Here's some of the fish that they bagged.

Two large mullets (F. Mugilidae). The larger one was longer than my foot!

Here's a closer look at the smaller mullet. This might be the greenback mullet (Liza subviridis).

After looking through my photographs, I now want to kick myself for not having taken any detailed shots of the larger mullet. Based on the the shape of the dorsal and caudal fins, it seems that it's a different species of mullet from the smaller one. I have no idea which species the larger mullet might possibly belong to.

I think this is a slender mojarra.

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Some sort of whiting (F. Sillaginidae). Sillago aeolus, perhaps?

The net was thrown again, and more fish were brought in.

My tentative identifications for these 3 fish are: slender mojarra (left), Kops' glass perchlet (centre), and deepbody mojarra (right).

A large catfish, the size of my foot! Sorry for using my foot as a point of reference so often, it's the easiest thing to use for comparison (My foot's about 26cm long, by the way).

It's obviously an eeltail catfish (F. Plotosidae). But it definitely doesn't quite look like the two species of eeltail catfish I've seen on many visits to our shores, the black eeltail catfish (Plotosus canius) and the striped eeltail catfish (Plotosus lineatus).

Could it be a white-lipped eeltail catfish (Paraplotosus albilabris)?

One of the guys told me that this sort of catfish is very expensive back home in Bangladesh. He said that they come here to fish once in a while, whenever they're able to take a break from work. Sometimes the catch is good, and they manage to net a lot of big fish.

The net was cast for a third and final time.

I have no idea what species of fish this is. If I had to hazard a guess, it would be a member of the Clupeiformes, a group of fishes that includes herrings and anchovies. Based on my copy of A Guide to Common Marine Fishes of Singapore, this could possibly be Dussumier's thryssa (Thryssa dussumieri), which belongs to the anchovy family.

A much larger deepbody mojarra.

A large fringe-eyed flathead (Cymbacephalus nematophthalmus). Once again, it's nearly the size of my foot.

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Two good-sized rabbitfish (F. Siganidae). Is this the streaked rabbitfish (Siganus javus)?

After this, the men left with their catch. The one whom I spoke to earlier on shook his head and commented that today's catch wasn't very good compared to previous visits. I'd like to see how much they catch on a good day.

As far as I know, fishing on Sentosa is illegal. But the opportunism of these two men provided a chance to document some of the fish that would otherwise be virtually impossible for me to find or photograph. Also, it shows how these artificial lagoons do support a rich variety of marine life, including fish fit for consumption.

The most exciting find of the night occurred when I came upon this lone tape seagrass (Enhalus acoroides).

As I took a closer look, I thought I saw something brown clinging to one of the leaves.

Peering into the murky water, my heart skipped a beat as the unmistakable shape of a seahorse came into view.

At that moment, all I could say was "Oh my God, it's a seahorse!"

Who would have thought that one could find a common seahorse (Hippocampus kuda) in an artificial lagoon at Siloso Beach?

The amount of sediment in the water was really hampering my attempts to take a decent photo of this amazing find. So I gently disentangled its prehensile tail from the seagrass, and brought it to shore. Naturally, it was very unhappy at this, and turned from pale brown to black.

This is the first time I've seen a seahorse on a southern shore. Feeling bad for subjecting it to such stress, and for not having brought a container along so that the seahorse could remain in water while I took the photos I needed, I quickly returned it to the seagrass.

Finding a seahorse definitely more than made up for the lack of common sea stars (Archaster typicus) tonight. And I certainly discovered that these murky waters, although seemingly lifeless, do contain plenty of surprises. My interest in finding out more about this special shore has certainly been piqued.

Does anyone want to attempt a muck dive over here? Who knows what lurks in the deeper parts of the lagoon?

The next time I visit this shore, I'm definitely going to need the following:

i) Containers. I'm not a fan of taking photos of marine animals in plastic containers, since I greatly prefer showing them in their natural environment. But given the murky water, and the fact that it's too easy for various creatures to swim away into deeper water and vanish, the use of containers will be a great aid.

ii) Nets. A few small aquarium nets, which would help me spend more time studying fish closely, instead of just seeing them shoot off into the depths before I can even react to their presence. Used in conjunction with a few small plastic containers, I don't have to worry so much about all the sediment in the water when I'm trying to take photos.

iii) Snorkel. I don't know if I'll be able to see anything though.

It's great to see that despite the heavy use of this shore, there's really quite a wide diversity of fish living in these waters. I really want to go back and explore this area more often, as well as check out the other islets that will require a bit of swimming to reach. Maybe an acquaintance of mine wasn't exaggerating when he said he saw a large barramundi (Lates calcarifer) swim past him at Palawan Beach...

This is part 2 of a 2-part series on a trip to Siloso Beach on 16th December, 2008.

Part 1: Siloso Surprises
Part 2: Fishy business on Siloso (this post)

Siloso Surprises


Most people are unaware that the swimming lagoons at Siloso Beach are actually quite rich in marine life. I've been wanting to explore some of these small islets off the main beach at low tide for quite some time, and besides, I also wanted to see if there was any noticeable increase in rubbish after ZoukOut.

I've got a soft spot for this place, even though it is really challenging. The water is extremely murky, and visibility is poor. If anyone tried scuba diving here, it would seriously be considered muck diving. Every step, no matter how gentle, stirs up a huge plume of sediment that instantly renders the water as opaque as a piece of cardboard. Unlike other shores that I've explored, there's no reef flat or otherwise flat areas of ground where marine creatures get trapped. There's only a gently sloping beach that suddenly drops off, and in some places, if you're not careful, you can suddenly plunge from your knees to waist-deep. The ground is mostly composed of a mixture of fine sand and mud that tends to crumble beneath your feet and slide down the slope, sending you into deeper water, whether you like it or not. Because of the profile of this shore, almost every fish, crab, prawn, or other motile organism that you spot will shoot straight for the murky depths before you can even think of switching on your camera.

And yet, with some patience, and a whole lot of luck, there's actually quite a fair bit to discover in such a difficult environment.

There are four of these artificial islets along Siloso Beach, and only one has a floating bridge that allows you to walk across. If I ever want to explore the other islets that are not connected to the main beach, I'll have to swim.

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One section of Siloso Beach has been cordoned off for some sort of development works, and wooden barriers have been erected to prevent people from trespassing. These are now draped with Sargassum seaweed (Sargassum sp.).

The tide must have been really high in order to hang all this seaweed above me.

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These wooden poles have been here long enough to become encrusted with acorn barnacles (Balanus sp.) and colonised by periwinkles (F. Littorinidae). Purple climber crabs (Metopograpsus sp.) can be found here as well, but they're really skittish and good at hiding amongst the fronds of drying sargassum.

The floating bridge itself provides a good surface for a great deal of marine life to settle down and colonise.

Here we have a thumbs-up sea squirt (Polycarpa sp.), and a pink flowery soft coral (F. Nephtheidae).

There's something reddish and flat growing on this part of the bridge. Could it be some sort of hard coral?

Here's a closer look.

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First time I've seen an onch slug (F. Onchidiidae) on this bridge. And here's a waved nerite (Nerita undata).

Common whelks (Nassarius livescens ) live up to their name, being easy to spot even on Siloso Beach itself.

I'm seeing this trend where some species that prefer the silty, muddier northern shores of Singapore can be found in the similar conditions of these artificial lagoons. This spotted moon crab (Ashtoret lunaris), which we normally find on Changi, is one such example.

Note to self: Moon crabs are extremely feisty, and if you try to catch them, they will pinch. HARD.

I finally crossed the bridge and ended up on the islet. There was some rustling in the bushes, and several times, I managed to spot rats (Rattus sp.) scampering in the shadows. That could be a reason why I couldn't find any land hermit crabs (Coenobita sp.). Some parts of the beach were covered with tiny balls of sand surrounding small round holes in the ground, telltale signs of sand bubbler crab (Scopimera sp.) activity. Larger burrows at the high shore hinted at the presence of a sizeable population of ghost crabs (Ocypode ceratophthalmus).

I've never found any moon snails (F. Naticidae) here before, but sand collars, which are the egg masses of these predatory molluscs, are quite commonly seen.

After a few frustrating attempts, I finally found a well-behaved purple climber crab that allowed me to get close and snap a few photos before scurrying off.

The blue swimming crab (Thalamita sp.) is commonly seen among the coral rubble on nearby Tanjung Rimau, but it seems to be found in respectable numbers among the large rocks found on both ends of the islet. This was just one out of four that I found within a small area.

Flower crabs (Portunus pelagicus) belong to the same family as swimming crabs, and juveniles of this species greatly outnumber the blue swimming crabs here.

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There aren't many shores where I can easily find both pearl conch (Laevistrombus canarium) and black-lipped conch (Canarium urceus).

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There were a few of these blue-tailed prawns (F. Penaeidae) in the shallows, and they were quick to swim for deeper water or bury themselves. And as you can see in the second photo, it doesn't take much movement to stir up all the silt and sediment, ruining your chances of taking a decent photo.

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It's impossible to miss the countless zoned horn snails (Batillaria zonalis), as well as the tiny tidal hermit crabs (Diogenes sp.) which inhabit the empty shells. I really must do a comprehensive survey of all the cerithid and potamidid snails in these lagoons and sort out which species inhabit these reclaimed beaches.

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There are two tiny patches of spoon seagrass (Halophila ovalis) next to the bridge. I still remember how excited I was when I first stumbled upon the seagrass almost 2 months ago.

Here's another creature more commonly seen on our muddy northern shores, a spiral melongena (Pugilina cochlidium).

I was joined by two Bangladeshi workers who had come to do a bit of fishing. With a few tosses of a simple cast net, they managed to haul in quite a few fish. More on their catch in the next post.

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Besides fish and random pieces of seaweed, driftwood, and assorted marine trash, the net also brought in a small elbow crab (F. Parthenopidae), as well as a blue-spined swimming crab (Thalamita sp.). I took a few photos before returning both of them to the sea.

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To my amazement, there was a solitary tape seagrass (Enhalus acoroides), at one end of the islet. How does it manage to get enough sunlight in these turbid waters?

I tried to find the common sea stars (Archaster typicus) that I'd found on previous visits, but despite my best efforts, I couldn't. The water was too murky to get a good view of the seabed. I hope they're all lurking in the deeper parts of the lagoon.

The tide was rising, so I crossed the bridge back to Siloso Beach.

All the flotsam, both natural and manmade, creates a disgusting frothy mess.

Can you see the purple climber crab trying to clamber onto the shoe?

There doesn't seem to be more rubbish than usual. Looks like the barriers did their job after all in keeping the bulk of the litter from ZoukOut out of the sea.

But here's one piece of rubbish that definitely came from ZoukOut. There was a booth set up by DBS that was giving out these noisemakers at ZoukOut.

I decided to go take a look at the area that was used for ZoukOut.

This is the blue netting that I was talking about, which not only prevented people from sneaking in and out during the event, but also provided a barrier for most of the litter.

Most of the stages and platforms have been cleared, leaving behind these tents.

The beach is all quiet now, but just three days ago, there were thousands of people crammed into this area.

Most of the litter has been removed, although there are lots of small cigarette butts half-buried in the sand. And there are some bits of trash lying on the ground. But the situation does seem a lot better than I'd feared it would be.

Just outside the barrier, I found this ghost crab, alert and skittish as ever.

Red-eared slider (Trachemys scripta elegans)
I went to the toilet to wash up, and there was a red-eared slider (Trachemys scripta elegans) in the fountain!

Red-eared slider (Trachemys scripta elegans)
This turtle is a native of North America, and has been widely introduced to ponds, reservoirs, and canals all over Singapore. I wonder how this individual manages to find enough food to survive.

And as I walked to the Beach Station to take the Sentosa Express back to VivoCity, I passed a pond full of various species of frogs and toads, calling for mates.

Common Asian toad (Duttaphrynus melanostictus)
I managed to take a photo of Singapore's most common amphibian, the common Asian toad (Duttaphrynus melanostictus).

Coming up: I came upon a few very interesting fishy finds, which more than made up for the lack of sea stars.

This is part 1 of a 2-part series on a trip to Siloso Beach on 16th December, 2008.

Part 1: Siloso Surprises (this post)
Part 2: Fishy business on Siloso