Murder of our marine life at Pulau Semakau

It was a depressing end to a Pulau Semakau trip that I had looked forward to. Witnessing the aftermath of a murder of our marine life was not what I intended to experience.

Not sure if this group was the culprit, but they appeared to be fishing with rods in their hands, in the vicinity of the island....

This huge drift net was the tool used for the act, and I bet these murderers didnt care that possesion of nets as a fishing gear is illegal in Singapore under the Fisheries Act.

A key criticism of the use of drift nets was its consequence of unsustainable fishing. In addition, this technique also caused excessive necessary harm to unintended targets such as marine mammals.

This morning, intentional or unintentional, the driftnet placed by the irresponsible caused the precious lives of 3 Blacktip Reef Sharks (Carcharhinus melanopterus).

Ironically, I had always wanted to sight these sharks previously. On many occasions, I had failed to see them despite my friends' attempts to point out the predators of the ecosystem swimming in the Phase 2 landfill cells. Today, my wish was granted in a brutal way.

This first shark that was caught in the net was about 1.5m long, had fairly fresh wounds on its body and probably died not too long ago.

The 2 other dead sharks were of smaller sizes, probably 0.5m - 0.7m long. I imagine them to be a family swimming together, unaware of the lurking danger. Perhaps they swam too quickly, failed to notice the net and ended up entangled.

It was really painful to examine the scars on the carcass caused by the driftnet.  

With the help of many, the drift net was cut and dispose of to prevent future repeated use. Regardless, this is a short term solution that will not stop history from repeating itself again. We destroy one, the irresponsible replenishes with a new one, and the crime begins again.

10 out of 10 of my friends were sure that sharks do not exist in our waters. If such irresponsible and unregulated fishing continues, this myth will become a reality. It is amazing that there is a lack of ownership of the issue, probably because this falls into a supposed grey area that doesnt come under anyone's purview.

While I often speak about the purpose of Project Semakau to many, this morning was a stark reminder of how real the urgency and importance of the project is.

The longer the status of our precious shore at Pulau Semakau remains status quo and not elevated to that of a marine park, the higher the risk we run of losing our rich biodiversity. This loss, is a nightmare I wish none of us will have to witness.

Guided walk at Semakau on a stormy afternoon

We were back at Pulau Semakau on 4 Apr, for a guided walk with the students from Tampines Sec. Upon reaching the island, the looming dark skies spells of bad weather.

The perfect timing saw us seeking shelter at the entrance of the secondary forest - just as we reached the entrance point after the walk from the Visitors' Centre, the rain started pouring! Our hunter-seekers were already ahead of us, and I wondered if they too were seeking shelter in the forests.

After almost an hour, the rain though subside, continues to fall. The students, however, were not daunted a single bit and were really eager to start the walk.

With the absence of thunder and lightning, we braved the rain with our ponchos, for an hour of marine adventure.

Unfortunately, the first sight that greeted us was a drift net placed by irresponsible people. It had caught several fishes that were already dead. Drift net fishing not only results in unsustanable fishing, it also causes unnecessary harm to other marine animals that fishermen do not intend to catch. I shared the intention of Project Semakau with the participants, who concurred with the idea of gazetting the shore of Pulau Semakau as a protected area.

We visited the resident Anemone by the edge of the seagrass lagoon. Unfortunately, we didnt see the Anemone shrimp taking shelter under its usual host. The Anemone may look harmless, its lashing tentacles have stinging cells that may cause pain and discomfort to the skin.

Trotting on, I was glad to see the usual suspects at the sandy shore. The Sand-sifting Sea Star (Archaster typicus) is a good burrower of the sand (thus its name) and has a water vascular system to bring nutrients and oxygen through its body, unlike the blood circulation system in human beings. 

My heart almost sank when I saw the Hairy Crab (Pilumnus vespertilio) at one of the stations. The hunter-seekers had prewarned us that the showcase of a Hairy Crab at a station indicates the desperation of the unsung hero(ine)s. We couldnt ask for more, because animals were pretty much hiding after the downpour.

Named after its hairy appearance, this crab is slow in movement as compared to other crabs. To make up for the speed, its appearance allows it to camouflage really well both in water and on land.

Kudos to some keen eyes, the less common Heart Cockle (Corculum cardissa) was spotted! A bivalve, the Heart Cockle's 2 valves are separated by an opening that cuts through the middle. A victim to over-collection of its shell, it is often marketed as a token of love sometimes at a fairly cheap price, thus popular among couples.

A Ovum Cowrie (Cypraea ovum) was also seen moving along the surface. Another victim of over-collection, its shell was once used as a form of currency in the past. I wondered how that money system worked though, nonetheless glad its no longer the case else this snail would be extinct by now! The cowrie maintained its smooth and pretty shell by covering it with its own mantle, which protects the shell from any abrasion and scratches.

Not sure what the common name is, but the very uninnovative me calls it the Green Nudibranch (Ceratosoma sinuatum). Nudibranchs are named after the naked gills exposed at its back, which it uses to breathe. Interestingly, they are actually hermaphrodites, possessing both the male and female reproduction organs.

I was really happy to see the Cushion Star (Culcita novaeguineae) that is no longer as juvenile as a few months back. In its teenage months, this individual has clearly become rounder. This shape, coupled with a calcified body, makes it difficult for predator to prey on it. Hope that it will soon grow into a healthy adult!

Thanks to the hunter-seekers who braved the storm to find us a Knobbly Sea Star (Protoreaster nodosus), often the highlight of any guided walk. This species of Sea Star, named after the knobs on its body, is endangered on our shores and has fallen victim to the aquarium trade. I once saw one in a store at Plaza Sing, clearly looking undernourished. Human beings is one 'predator' that the calcified Knobbly cannot run away from.

The Fan Worm (Sabellastarte indica) was one of the few who gamely displayed its beauty on this rainy morning. Its feathery tentacles opened broadly, looking just like a fan and was probably lashing through the water for very tiny food particles. The tentacles is often the only part of the fan worm that is exposed as it lives in a self-made tube of its own mucus, sand and particles. Any detection of danger results in the tentacles retracting into the tube at lightning speed, which often wowed the participants.

Despite the bad weather, we still managed to experience the life of our shores. The participants' spirits were not dampened, instead are more willed to visit our shores again for more exciting encounters.

First guided walk at Pulau Hantu - 2 Apr 2010

My first public walk of the year was at Pulau Hantu. My group consists of participants who were not new to intertidal walks as they have joined us on walks at Pulau Semakau previously. Their enthusiasm and interest in nature made guiding very much enjoyable!

The island is actually made up of two islets: Pulau Hantu Besar (Big Ghost Island) and Pulau Hantu Kechil (Little Ghost Island), and is aptly named as "island of ghosts". It was here that 2 great ancient Malay warriors dueled fiercely to their death. The gods then transformed the two warriors into islets and their ghosts are said to wander the isle.

Warriors wannabes?

Despite its proximity to the Pulau Bukom's refineries, a wide variety of corals can be found on Pulau Hantu coupled with fairly rich marine life. Our first star (pun not intended) of the day was the Sand-sifting Sea Star (Archaster typicus). These 2 individuals had a few shorter arms probably chomped off by predators. Although they can regenerate their arms, it is a long process and I would imagine it to be quite an unpleasant experience.

We were thrilled by the male Fiddler Crab's (Uca spp.) morning greetings. It was really quite a spectacular sight to see them waving their enlarged claw, as if playing the fiddler. Not sure if it was the mating season, but they sure were eager to capture attention. We even saw 2 fighting each other, likely for territory or a mate. The enlarged claw is a great asset in courtship, as females are likely to be attracted to those with larger claws since it is quite a feat to be able to survive with this 'liability' which requires more to maintain.

 

The Hairy Crab (Pilumnus vespertilio) attracted praises of  'so cuuuute' as it hid in one corner of the container. Also fondly known as the Teddybear crab to some, the Hairy crab got its common name from its appearance. The hairs fluff up when the crab in water thus breaking its outline and results in some really good camouflaging performance. Note that this is not the Hairy Crab some Chinese deem as a delicacy, in fact, this crab is mildly poisonous.

The Orange Striped Hermit Crab (Clibanarius infraspinatus) was quite shy that day, and there wasnt time to wait for a nice photo opportunity. Unlike real crabs, the hermit crab actually has a soft abdomen thus requires the protection of an empty shell as its home. So, think twice when you next think of collecting an empty shell from the shore 'cos you may be depriving our friend of its potential home.

My guests laughed when I asked if the Black-lipped Conch (Strombus urceus) reminded them of a woman's lips with black lipstick. Like other Conches, the Black-lipped Conch also uses its operculum to hop along the surface.

The Spider Conch (Lambis lambis) is named so, after the spikes on the sides of its thick shell, resembling the legs of a spider. The conch's humble appearance makes it difficult to spot among its home, but turn it over, you will be awed by its pretty shell, just like many of our participants were. Apart from being a master of camouflage, the Spider Conch is a great pole vaulter with the use of its knife-life operculum to hope along the surface.

This is a probably a Wandering Cowrie (Cypraea errones) strolling around, 'feeling' and 'tasting' the water with its siphons. This snail is a great master at maintain its looks. See the shiny and smooth shell without scars and scratches, all thanks to its intelligence use of its own mantle to cover its shell. While I have all praises for the cowrie, I wish its shell wasnt as pretty to prevent it from being a victim of over-collection.

 

Nudibranches never fails to fascinate me with their bright colours. 'Nudi' is translated as naked in Latin and 'Branchia' as gills. The Nudibranch's naked gills (see the feathery structures) is thus what gave its name. This sea slug actually possesses a shell when young, but sheds it thereafter. It thus develops defense mechanisms such as bad tasting glands, and depicts the poison through its bright colours to warn predators.

Heres the pretty Chomodoris lineolata.

   

The colours of the Black Margined Nudibranch (Glossodoris atromarginata) were also fascinating.

   

While the Phyllid Nudibranch (Phyllidiella pustulosa) may look puny and cute, it is actually deadly to other marine life. Try placing this nudibranch in an aquarium , stress it and the entire tank could be wiped out by the milky substance it secretes. This is typical of its family which feeds on poisonous sponges, and concentrate the toxin in its tissues as a defense mechanism.

    

An animal that many people can recognise at first sight, the Jellyfish (Chrysaora sp.) can sometimes be seen at our popular beaches at Changi or East Coast. One should avoid touching one though, because of its stinging tentacles. A friend had complained of discomfort after being stung by a jellyfish during her swimming lap of a biathlon.

   

Giving us the Puss-in-boots looks was this Octopus (Order Octopoda), known to us as one of the smartest invertebrates that can recognise its tracks and even open the lids of jars. Another master of camouflage, it can change its colour and even texture of skin to match that of its surrounding within the snap of the finger, all thanks to special pigment cells.

My favourite of the trip was this Red Feather Star (Class Crinoidea), although it reminded me of the feather duster my mum used to cane me with. Although it has a mouth in the middle of its top surface, the Feather Star feeds by filtering small particles of food from the sea water with their feeding feathery arms. Like other echinoderms, the Feather Star has a symmetry of 5 - this individual apparently has 25 arms (go on, count it!).

Right beside the Feather Star was a humble looking (and therefore very well camouflaged) Onch slug (Family Onchididae) that I did not spot, if not for Ruixiang's obvious hint. Breathing through simplified lungs, this slug is more related to land snails and slugs. Its often seen on the surface of rocks as it is where it finds algae, its source of food. Without a hardy shell, the Onch slug secretes a supposed bad tasting mucus that covers its skin to ward off predators.

An intertidal trip is always precious and never possible for one to see everything. Apart from having to abide by the rules of the changing tides, our marine life roams freely and is thus never predictable. Such is nature, but this also make every experience special and unique. Come explore our shores and sign up for the next available trip! 

Guided Walk at Semakau - March 2010

A group of students from Nan Hua high school joined me on a morning of adventure at Pulau Semakau. They were the Green Reps/ Ambassadors of their school, and I hope they will take home the message of conservation, and the 3Rs (Reuse, Reduce, Recycle) for sharing with their friends.

Once again, we were all intrigued by the rich marine life on our shores - something that many of us do not expect.

Apart from this Dragonfish Sea Cucumber (Stichopus horrens) that the hunter-seekers found, our group also saw 2 others as we waddled through the 'deathzone' of the seagrass lagoon. This species of Sea Cucumber is said to melt and disintegrate when exposed in the sun for too long. It can also shed its skin when stressed, so be sure not to disturb it unnecessarily.

Often thought to be a worm by first-time visitors to our shores, the Synaptid Sea Cucumber (Family Synaptidae) was a great show-and-tell partner. As I  was introducing it to the crowd, it gamely showed us how it lashes its beautiful tentacles to feed on detritus in the water.

The participants treaded carefully for fear of stepping on a 'land mine' - the Sandsifting Sea Stars (Archaster typicus)  were half buried in the sand. Camouflaging fairly well into the surroundings, we might just step on one if we don't watch our step. While they do not have a brain, and might not feel any pain, we can never be sure, can we?

I must apologise for the photo that doesnt do the Knobbly Sea Star (Protoreaster nodosus) any justice. Apart from being the icon for Project Semakau, our Knobblies often awed our visitors with its vibrant colours, pretty knobs (that gave its common name) and its sheer size (it can grow up to 30cm wide!). This Sea Star has a calcified body which makes it difficult for predators to prey on it.

Although mildly venomous, be sure not to touch the Black Long-spined Sea Urchin (Diadema setosum) as the spines can give painful stings if stepped on. The brittle and needle-like spines makes it challenging to extract it from our flesh too. In addition to being a defense mechanism, the spines , in partnership with the Sea Urchin's tube feet, helps it to walk.

My first time seeing a Juvenile Noble Volute (Cymbiola nobilis) whose shell is of a much darker shade. We were really lucky to see a pretty adult too. Unfortunately, this snail's existance is threatened due to habitat loss and over-collection of its beautiful shell - I have seen ,on several occasions, bazaar stalls selling spoons made from the volute's shell!

The Spider Conch (Lambis Lambis) may look unattractive at first glance, but I never fail to hear the visitors' 'Wahhhhh' when I turn it over to show its underside. Named after the spikes on the shell's edge that resembles the legs of a spider, the Spider Conch has a strong operculum and foot that allows it to pole-vault away on the surface.

Our adorable Polka-dot Nudibranch (Jorunna funebris) made a guest appearance too. Named after its exposed naked gills (the feather like structures), Nudibranchs are sea slugs and actually have shells when they are young, but sheds their shell thereafter. They thus develop other defense mechanism such as having warning predators that they are distasteful or poisonous with their bright colours.

Its my first encounter with this Nudibranch (and I believe its a first record for Semakau!). Not quite sure what species this is, but it certainly is huge, almost as long as the length of my 26cm chopstick!

Nearby, we also saw these egg ribbons, not sure if it was the eggs of the Nudibranch, but certainly a good sign that our shores are thriving with life!

It was Bull's eye for the group on their guess of how the Flatworm got its name - 'cause they are really flat! Pseudoceros sp.  was the only species we saw that day and the participants were surprised to hear that the flatworm is a Hermaphrodite which possesses both the male and female reproduction organs. Unlike us, flatworms have no circulatory and respiratory organs,instead oxygen and nutrients pass through their bodies by diffusion.

I had to remind the participants to be extra careful as we wade through the water near the reefs after noticing a few Sea Nettle Jellyfishes (Chrysaora sp.) pulsating near us - contact with their tentacles can result in quite painful stings! Jellyfishes also do not have specialized  respiratory, or circulatory systems as their skin is thin enough for the body to be oxygenated by diffusion.

Another Jellyfish we saw was this Upside-down Jellyfish (Cassiopea sp.) which gives a milder sting that can cause skin irritation with an exceptional itch. No prizes though, for correct guesses on how it got its common name. This Jellyfish harbours a mutually beneficial relationship with zooanthellae (single-celled photosynthetic algae) that is housed in its body. The algae shares its food with the jellyfish who in turns provides a home and minerals for the algae.

Occasionally mistaken for the Upside-down Jellyfish, the Hell's Fire Anemone (Actinodendron sp.) is one you don't want to mess with. Aptly described by one volunteer, the sting from this Anemone burns you like how a fire will, and hurts like 'hell'. Although I have no personal experience to speak of, I sure don't want a taste of that feeling. One can identify the Anemone by its radiating white stripes from its centre disk, and its branching triangular-shaped tentacles.

We were really lucky to see this Heart Cockle (Corculum cardissa), not as commonly seen due to overcollection of its shell. A simple googling will show you how its being marketed as a token of love, sold a fairly cheap price. Little do couples noticed that this clam's opening of the valves cuts vertically across the centre of the 'heart', just like how we often depict a broken heart. In my opinion, a bad omen and not a good token of love at all!

Per usual trips, we had a chance to visit our resident Fluted Giant Claim (Tridacna squamosa), but for as long as we keep the environment protected, clean and for its growth. Unlike most other bivalves, the giant clam harbours single-celled algae ,in its fleshy body, which produces food through photosynthesis. To maximise its "farm", the clam exposes these algae to the sunlight by facing the mantle to sunlight, at the same time, giving us a wide smile!

Yet another fruitful trip to round up my intertidal walks in March. =)