緑の道: 023. Pulau Sekudu Mini Series 3/4

… and I am not talking about the sudden question one of my hallmates raised pertaining to my moving out next semester or the fish tanks that’s just 1 room away from the lab that I am currently hanging out in (sounds casual but the atmosphere points a 180 degree-otherwise).

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Besides the above sponges and blankets of seaweeds (and seagrass – not the above picture though), we bumped into few finned-surprises. =)

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From afar, these cluster which wriggled and flickered through the shallow pools of water on Sekudu Island resembled tiny tadpoles from a distant. But taking a look at the ‘ball’ of sperm look-a-likes revealed creatures which were far from being amphibian.

*drum rolls* Presenting Striped eeltail catfish (Plotosus lineatus), with their vanilla stripes, are quite the frequent visitors of Singapore shores. They are currently the only catfish found in coral reefs. Small ones, being more vulnerable, tend to congregate into a ball of squirming wrigglies (like above). Even when it moves from one place to another, they continue to remain in a ball. However, larger ones can either be found in smaller groups or by itself.

Although they may seem harmless, appearances can be deceptive. The sawed spine on the dorsal fin (fin that’s situated at top) and on each of the pectoral fins (fin situated at the sides) are venomous. Its sting can pack quite a punch; and at times, may even send the victim 6-feet under. We must have quite a masochistic streak, if the fact that the aquarium trade for these fish are popular is true. As they get bigger, not only do they eat their tankmates, they have also being known to indulge in cannibalism. >_< Reminds me of the Black Ghost Knife which my friend once kept.

Can you find it (but then again, these pictures are an easy guess, the object will usually be smacked right in the middle :D)? This masquerader of the sandy shores is none other than the Largetooth Flounder (Pseudorhombus arsius). Unlike the chubby Flounder in ‘The Little Mermaid’ (by the way, Flounder isn’t a flounder –.-), the Largetooth is as flat as a pancake.

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(left): One way to tell apart the Largetooth from the other flatfishes is that the caudal fin of the Largetooth’s is clearly separated from its dorsal and anal fins. Can you spot its eyes? Though flat and oval-shaped, the flounder isn’t symmetrical (right). In fact, the eyes are situated a bit to the left (towards the dorsal fins) [2].

(right): If turned around to its ‘blind side’ (since both eyes are on the other half), one can actually see the distinctive shape of a fish. A carnivore of the sandy and muddy substrates, this particular fish has its mouth filled with teeth, especially enlarged canine ones [3]. Even so, that does not faze us two-legged ones one bit, as they are often used for human consumption.

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Another fish that we bumped into which laid flat on the substrate was the Filefish (family Monacanthidae). Its common name is inspired by its rough, sandpapery skin, which was said was once used to finish wooden boats! But unlike the flounder, the filefish has one eye on each side. The first thing that usually comes to mind when most of us see a fish lying flat on its side without a movement or sorts is to label it as door-nail dead. And that’s why assumptions should always be voiced out, better to have our mistakes pointed out and be learned than be silent and wrong. =)

One reason why the filefish behave as so could be because they aren’t really Michael Phelps material. :) Their small fins confine them to a sluggish gait, hence they are often seen drifting head downward amongst seaweed. Playing ‘dead’, it’s presumed that the filefish does so to fool both prey and predator alike. Their menu differ with species, so some might favour algae and seagrass, while others satiate their hunger with small benthic creatures (e.g. tunicates, gorgonians, and hydrozoans) while a few are knowned corallivores (coral-eaters) [3].

Fancy some dried Filefish? Apparently Filefish jerky or 쥐포 (jwipo) is a popular snack food in Korea. It is typically roasted before eating [4]. Learn how to cook dried file fish jerky here. Not sure if this stuff can be bought in Singapore in the first place. :P

Suddenly, a shout rang in the air. It appears that something has gotten stuck to LK’s booties and it ain’t chewing gum. Lifting up her leg and you can see what caused a sudden rush of activity at the pool yonder.

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Stuck to the booties by its spine was a toffee-coloured Mangrove whipray (Himantura walga). Apparently, Pulau Sekudu is famed for its rays, and one may unknowingly step onto a sand-hidden one if not careful. Most stingrays have 1 spine often at the base of the tail where it (the tail) meets the body. The spines are jagged and can cut deeply and secrete venom into a penetration, causing one heck of a sting. But even so, the spine is not used by the ray to hunt but for self-protection (but if lost, rest assured, it can be regrown). Hence, most stingray injuries at shore can only be blamed upon our own negligence towards our surroundings. As it blends well with the sandy substrate, it’s therefore always better to be one step at a time when treading through such territory.

Despite its common name, the mangrove whipray is not usually found in mangroves. Instead, it’s more commonly encountered in clear-water lagoons over sand and rubble, near coral reefs. The name of mangrove whipray comes from the description by Macleay of an immature female specimen caught near mangroves off Port Moresby, Papua New Guinea [5].

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The second kind of ray spotted was the Blue-spotted fantail ray (Taeniura lymma) (pun intended)! As there’s a broad skin fold under the tail (left), it’s also sometimes known as the Blue-spotted ribbontail ray. Its tail is also long and thick with two blue stripes running down the length. With the rising tide, the ray will wade into shallow, sandy areas to search for snails, clams, worms, shrimps and crabs. As the tide ebbs, this nocturnal creature takes shelter in caves and under ledges. This one, unlike the Mangrove whipray, is rarely found buried under sand [6].