緑の道: 026. Pulau Semakau 1st Hunt – Stop & smell the roses! (25th July 2009)

Edited.

Well, metaphorically at least. But that’s not to say that the shores are devoid of flowers. Within the mangroves, sea hibiscus provides a cheery-sunny view with its red yellow flowers. Amongst the seagrass lagoon, when it’s within season, tiny pearl-white beads of the tape seagrass pollen can be seen floating en masse towards its female counterpart (more of it in the 2nd hunt).

Another flower, an even prettier sight to behold when embraced within the lapping waves of the sea, is the anemone. However, these are far from the floral ones that grace the terrestrial fields. Many have said they share a resemblance to each other, appearance-wise. But that’s where all similarity ends. One attracts bees while the other can sting like one. >_< I must say, the fella who was responsible for bequeathing the marine creature its common name must had fancy plants quite a bit. Even with the images below, it takes quite a bit of an imagination to be able to see where the similarity overlaps.

Once equipped, it’s towards the shores we made our way as the sun slowly rose from its mauve folds of comforters. This time round to Semakau Island involves putting on our “hunting caps” and keep a sharp eye for any lurking creature, whether its beneath sandy terrain of soggy sponge. Once found, the creature (or its species) is kept tabs on via keeping a survey sheet. These data would then be used as a baseline for monitoring purposes besides contributing to public use via the Project Semakau website. All this serves to enhance the island’s value as an education-cum-conservation site.

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Some of the first few creatures that made it to the data sheet my group partner, Tiong Chin and I was in charge of was these ~~nerites~~ molluscs. To the untrained eye, a glance of the top may reveal few but once flipped to its bottom, the markings and bumpy edges tell a different story for each species. However, to a conchologist (mollusc and shell expert), the shape or the texture are a big enough giveaway of their identity.
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(left): Previously thought to be a nerite turned out to be a Toothed Top Shell Snail. Translated literally as the ‘One-toothed lip’, the Monodonta labio indeed has a single, tooth-like protrusion at the lip of its opening. And unlike the thick trap-door which the nerite on the right possesses, the M. labio has a thinner trap-door (aka operculum) that is made of corneous or horny material. Flexibility-wise, this allows the snail to withdraw deeper into the dark corner inside its cone-like but asymmetrical shell – not from the curious glances of a piqued audience, but from the voracious prying of shore-inhabiting crabs.

(right): Compared to the snail in the left picture, nerites like this Nerita chamaeleon has a thicker trap-door. In fact, the variable hues in which a operculum can come in plays an important part in nerite ID. However, the Nerita chamaeleon or the Chameleon nerite earned its namesake for showing great variation in shell markings and colouration. Thicker in operculum relative to the Toothed Top Shell, the shape of the nerite is also different as in it sports a semi-marble figure. This unique semi-globular probably helps by extending its lifeline a little. Forget about eating, what use is lunch if it keeps slipping from one’s crab-by grasp? >_<

During the low tide, these nerites lead an ‘idle’ life and creep about slowly (if any at all) on the rocks garnished with lichen. In fact, their favourite low-tide spot would be one where the food source is readily available. Also, this must also include areas above tide line as no nerite in their right mind would enjoy being the next dish for quicksilver gobies etc [1].

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Next up on the introduction list, we have members of the Family Cnidaria. Never mind their tendency to be slow-moving (sessile for some), they can still ensure their survival on the reefs. Thank you very much. On the left – from Order Actinaria – the Banded bead anemone looked fairly similar to the coffee sweets I used to suck when I was a kid. When the tide ebbs, the tentacles of this true anemone are tucked into its body column, making it look like either blobs of glassy, spat-out coffee candy or beads of jelly. :) Although they can often be found in clusters, the banded bead is a lone wolf, a solitary polyp to be precise [2].

(right): Also Order Actinaria, the Giant carpet anemone (Stichodactyla gigantea) was next to be seen. With its capability to span about 40-50cm in diameter, the giant carpet anemone rivals the Haddon’s carpet anemone (Stichodactyla haddoni) in size. Covered in short tentacles so that it looks like an unkempt carpet, the giant carpet anemone has a folded oral disk (as can be clearly seen in the picture). Although it resembles the Haddon’s somewhat, it differs by lacking the fringe of long-short tentacles which the Haddon’s possess at its edge [3].

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Another characteristic that separates the Giant carpet anemone (Stichodactyla gigantea) from Stichodactyla haddoni is that the thin-tentacled giant carpet has a flashy underside compared to the plain one of the former. From shocking pink to royal velvet, rows of verrucae make eye-catching patterns on what can be termed as a splashy background [3]. Verruca, for your information, is a small, flattish, wartlike prominence –usually found growing at the bottom of the foot – and not the tantrum-throwing, greedy kid from ‘Charlie & the Chocolate Factory’ (though her existence could be likened to one).In fact, according to wiki, Dahl claimed that "Veruca Salt" was the name of a wart medication he once had in his medicine cabinet. Wicked sense of humour, he has (always had a fondness for his books)!

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(left): Found stuffed between a rock and a hard place was the Branched tentacle anemone (Phymanthus sp.) (Order Actinaria). In fact, that’s where they are mostly seen, wedged between crevices! :)

(right): Characteristic to these sea anemones are the fine branching located on their tentacles. As can be seen from the image, the slaty-grey body column has longitudinal rows of verrucae (just like the Giant carpet anemone, but less flamboyant) in white. When disturbed, it tucks its tentacles into the body column like so (the picture shows it’s half way there) [4].

Another household similar, an untidy mop this time round which we crossed paths with was the Swimming anemone (Order Actinaria). Though it has a pedal disk (the structure which attaches the anemone to the ground), it isn’t very sticky and the anemone can still swim by undulating its numerous manners in a coordinated manner. At low tides like this time, the anemones can be seen lying freely on the ground or attached loosely to the seagrass/algae. They don’t really swim all the much. When threatened, its been said that the anemones will lose its tentacle on purpose as distraction. Now attracted to the wriggling tentacle, the swimming anemone would make its escape (possibly by retracting its tentacles) while its predator’s attention is still elsewhere. Since its generally a slow-moving being, the anemones rely on their harboured photosynthesizing zooxanthellae (a type of algae) for food [5].

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Zooxanthellae-wise, the same can also be said for the Bubble tip anemone (Entacmaea quadricolor) (Order Actinaria). And just like the Branched tentacle anemone, the Bubble tip anemone is generally found nestled amongst hard walls (corals especially). However, the tip does not always appear bulbous but can be inflated at will. If bulbous, the band of white near the tentacle tip would be located somewhat near its “equator”. Not quite sure what triggers the inflation/deflation, though it has been related to the presence of anemonefish [6].

Let’s play a game of “Spot the Sunflower Mushroom hard coral”. How many can you find? =)
Clue: Yotsuba! ヽ(´▽`)/

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Though it has bulbous tentacles not unlike the Bubble tip anemone, the Sunflower Mushroom hard coral (Heliofungia actiniformis) is not a sea anemone but a hard coral of the Order Scleractinia. Free-living in its adult stage, the coral is commonly seen on Pulau Hantu and here at Pulau Semakau ^^v. Uniquely, it’s the only species in its genus Heliofungia and is considered to be the largest of polyp among hard corals. Yes, you guessed it. The entire mass is a single animal!

Besides being mistaken for sea anemones, the Sunflower Mushroom has also been mistaken for the Fungia Mushroom hard coral. However, telling apart these two can be seen using the picture on the left. The Sunflower Mushroom has large, rounded teeth on the skeleton walls (the rounded forms at the top in the middle) while this feature is lacking in the Fungia Mushroom Hard Coral.

That’s Tiong Chin there, my co-partner during yesterday’s hunting-seeking session, as he trudged through verdant beds of algae and seagrass as the hunt continued...