Semakau with the flatworms!

It has been a long time since I guided. Finally the projects and exams are over, I can visit the shores again! ♥

I guided with yw a group of hyper and interesting ITE Clementi students from the Green Club at 28 Feb (: Thats them crossing the seagrass, also known as the 'death zone'.

The seagrass lagoon is a very good nursery ground for the animals to lay their eggs and juveniles to live in. To minimise trampling and damage from people, a 'death zone' is created as a passageway.

Love is in the air for the sand sifting seastars. For the first time, we could not find a single seastar to talk about since they were all in pairs!

Though the seastars are stacked on top of one another, they fertilise externally. This position only helps to increase the chances of fertilisation. The male, being the smaller one, is usually at the top. I have seen them swimming in this position before! (;

That's yw talking about the seastars..

Can you spot the anemone shrimp? The five-spot anemone shrimp gets protection from the anemone's stinging tentacles and feed on any remaining food of the anemone.

The flatworms (group) was excited to see the Knobbly Seastar. They may appear to be poisonous but they are not. Their knobs help to deter their potential predators. These knobblies prefer to feed on snails and clams though they do eat sponges and soft corals as well.

Mushroom corals are free-living animals and live singly. When it is young, it is attached to the ground with a stalk, just like a mushroom. The stalk eventually breaks off as it grows older. Food is passed in and out through the central opening.

The seahorse is a true fish! Being a poor swimmer, it can hook itself onto seagrass to prevent itself from being swept away. Few things I admire the seahorse about:

1. With no stomach and a simple digestive system, the seahorse eats a lot continuously and the babies can eat up to 1000 shrimps! I eat alot ended up accumulating the fats zz.
2. The male gets pregnant instead of the ladies. As ladies deposit their eggs in the males' pouch where it get fertilised.

The giant clam feeds in two ways. Besides filter feeding, the algae found on its mantle can make food and contribute to its nutrient intake. Its mantle is eaten by people in some countries. Its lifespan can be up to 100 years!

Not a very clear shot of the stonefish sea cucumber. It is edible but must be properly treated as tests have shown that it contain toxins.

A pretty nudibranch (Jorunna funebris) was found by the hunter seekers. It is carnivorous since it feed on immobile and slow-moving creatures like sea anemones and corals where they acquire their toxins. Its pair of rhinophores in front is used to detect chemicals in the hunt of their prey and mates while the flowery gills at the back is used for breathing.

We also saw a rather big cowrie (about the size of my palm!) found by Robert. A pity it was dead though.

Despite the hot weather over the weekend, it was a good trip and I hope the participants had enjoyed too!

Knobbly seastar galore!

Did line transect with Kim at 27 Feb. Saw many many knobbly seastars!!! (thanks to July)

Never seen so many of them at one time. Semakau never fail to surprise us all (:

In conjunction with the International Coastal Cleanup Singapore 2009, we had the first cleanup at Semakau together with the HSBC and Ministry of Environment and Water Resource(MEWR) volunteers. The RMBR nature guides did the cleanup at the mangroves, while the HSBC and MEWR volunteers did the cleanup at the coasts. All sorts of rubbish were found including tyres and big styrofoam pieces were found! Fishing nets are the headache as fishermen leave their nets discarded among the roots causing many creatures to get stuck. It was a refreshing experience as I totally did not expect the mud to be that soft. We had to crawl almost hip deep in the mud to remove the litters!

Although the cleanup lasted for about 2 hours, we have only cleaned part of it and there were certainly more trash to be cleared of! Of course we could not clear everything but to try our best in doing whatever we can within our own limits.

People dispose their trash into the sea carelessly, not knowing (or do not care about) the resulting consequences. These rubbish are swept to the shores, some animals may mistaken them as food and pollute the environment. Such cleanup sessions give us the opportunity to give back to the environment. Well if we do not clean up our own beaches, who else will?

*Sorry for the lack of pics. Will post more pics once I receive them.

On the way to the intertidal flats, we spotted these feet markings on the sandbars. It belongs to the Monitor Lizard!(Thanks SY.) It probably come here in search for seafood eh.

That's sea turtle with Prof Tan crossing the 'death zone'!

A trail has been marked out in the seagrass lagoon for visitors to past through and this zone is known as the 'death zone' as no organisms are able to live in there. This is to prevent people from trampling all over hence minimizing the damage caused .

This spider crab was spotted by Prof Tan! They are hard to spot as they move slowly and camouflage really well with the surroundings. They are named after their long and skinny legs. Though they are small with a body width of 2cm, they belong to the same family as the Japanese Spider Crab- the biggest crab in the world! Its leg span can reach up to 4m!!

As a comparison, I have found this picture to show its size as compared to us!

Heart Cockle!

Unlike other bivalves, this shell opens at the centre vertically! People have been collecting their shells as a prove of their love to their other half. Isn't it ironic how people use such heartless methods to prove their love??

Giant clam can grow up to 227kg and 1.2m across! They are facing extinction due to overcollection of their shell and meat! They are eaten as a delicacy in certain places and their shells were used as ashtrays.

This noble volute is actually a very beautiful creature. Its body is even more attractive than its shell. This is a mother noble volute who is laying eggs. It's nice to see these animals are surviving well (: The noble volutes feed by suffocating the other bivalves till they have to open up their shells to breathe. Then it will scraps them off their shell to eat! Not so noble isn't it?

This jellyfish is usually found upside down as they habour zooxanthelle (symbiotic algae) in their tentacles. The algae photosynthesises in the prescence of sunlight hence provide food to the jellyfish. The upside down jellyfish in turn provide a home and minerals to the zooxanthelle.

We saw many other organisms but I didn't manage to get their pictures ><

• nudibranch
• flatworms
• 4 Knobbly sea stars!!
• Cushion Seastar (A big one!)
• Spidercounch
• Seahorse
• Carpet Anemone
• Synaptid Sea Cucumber
• Sandfish Sea Cucumber
• Ocellated Sea Cucumber
• Squid
• Dead Cowrie

Soon it was time to leave..

and the sky was looming with dark cumulonimbus clouds.

The kids could not bear to leave and bidded farewell as they leave their tracks in the sand.

Many thanks to the hunter seekers, we saw many great stuff yesterday! A big thank you to my participants as well for making this yet another memorable trip! (:

WOA what have we got here that attracted everyone's attention and snapping away with their cameras?

Sunrise!! Nice~ if only there's dolphins as well q;

Guided a bunch of enthusiastic happy people today, thanks mudskippers for making this walk such an enjoyable one!

Peek-a-boo seastar!

Soft corals- dead man's fingers!

It's best not to touch these soft corals as they have stinging cells. At low tides, it may look uninteresting as they flop over one another. But during high tides, they extend their polyps as they feed on planktons and it looks really beautiful! However its 'fingers' may look like calling out for us to join them and it is kind of eerie hence the name 'dead man's fingers' (;

There were plenty of red seaweed around! Compared to the green seaweeds, they can survive in deeper waters as being red allows them to photosynthesise in lower light levels. //edit (Thanks Ron) The 'nori' used in Japanese sushi is made of certain types of red seaweed. Some red seaweed are also used to make 'agar-agar' in jellies and stabilisers in processed food such as cholocate milk and yogurt.

Out of so many organisms in Semakau, my favourites are flatworms and nudibranchs (: They come in such vivid colous and patterns! They are poisonous since they feed on sponges and corals. That is where they acquire their toxins from as this is warned to their predators by their bright colours!

//edit. As we venture further in, we saw a school of fishes! It's best not to approach too close these fishes as we do not know if these fishes have protective mechanism like venomous spines.

Another red flower crab that was ready to fight us out. This swimming crab has a pair of paddle-like legs at the back allowing them to swim faster than other crabs. //edit. The male flower crab has brighter colouration in blue whereas the red female crabs come in duller colours. Now why the flower crabs that I usually see seem to be ready to declare war with me S:

The highlight of the day was the Aerobatic Flying Displays!

That was a bonus to all of us! We were awed by the displays and that certainly stopped most of my participants in their tracks! The airplanes had captured my participants' attention and boy was I jealous!

The trip ended off with holiday mode for the participants...

and I spotted two olive-backed sunbird within such close proximity on the way home! That certainly ended my day on a perfect note! (:

//Thanks Ron for the edit! (:

Set off to Semakau again last Sunday (: always love the skies on our way there.

Nice clouds!~

Guided with Kim today (: Our group- horseshoe crab passing the seagrass lagoon.

The moon snail may look gentle but it is actually a ferocious predator! They can suffocate the bivalves and if they still refuse to open up their shells, the moon snail can secrete acid to soften their shell and suck them out! So now when you see empty seashells with a hole on them, you know who's the culprit huh.

Strawberry topping on the chocolate sponges!

Aha that was described by one of my participants (; Sponges do come in varied colours and shapes. Sponges are cosy home for animals to stay. With the constant flow of water, it acts like air-conditioning for the tiny animals living within. They can eat the bits of food flowing in with the water too! Some animals like the velcro crab use the sponges as their protection as well as sponges are poisonous and distasteful to some animals.

This pic depicts a budding sponge. Sponge reproduce both sexually and asexually (for this case). So when a sponge buds, a part of the parent sponge falls off and this grows into a new sponge.

We saw many other organisms but did not manage to take a picture of them as was busy guilding.

Some of them include:

1. Seahorse
2. Spidercounch
3. Dead Cowrie
4. Octopus
5. Cushion/common/knobbly Seastar
6. Stonefish Sea Cucumber
7. Sunflower Mushroom Coral
8. Fanworm

Another great trip! It's interesting to see how the kids got fascinated by the intertidal animals (; Thanks rmbr for organising and horseshoe crabs for being such attentive audience despite the hot weather!

Some other entries to check out!

Eunice

July

SY

KS

Went to Semakau at 4+ am to guide a group of PLMGS girls. There they are posing as our group- upsidedown jellyfish (;


During the walk to the intertidals, we saw an obstructed view of beautiful sunrise!! How often do we get to see this in mainland Singapore? Never in fact, with all the highrise buildings.

Horseshoe crab is spotted by one of our participants (: It is a harmless creature, often seen burrowing quietly into sands feeding on worms, clams and anything edible including dead animals. They may also scrape off algae. Another interesting fact: It needs to exercise in order to eat. It has no jaws. So walking movements grinds up their food, and its bits are then passed on into its four pairs of 'food processing' legs!

Also their blood has a substance that is so sensitive to bacteria that 10% of them died in the process of harvesting to test for the presence of bacteria in human medication. Thank goodness a team from NUS Dept of Zoology has cloned a substance with similar characteristics to replace these wild harvested horseshoe blood.

As they grow, their body shape become rounder and looks like a cushion!~ More often seen in diving, hence always a TREAT to see them in shores. They have been seen on feeding some species of hard corals and their diet include immobile animals, organic particles found on sand and seaweeds.

Upside down jellyfishes passing the 'dead sea zone'..

That's hen talking to our participants. Guided together with hen today (:

Juvenile Giant Glam.

That's a giant giant clam haha.

Giant clam feed in both ways. Besides filter feeding for food, the zooxanthelle (symbiotic algae) is also present to make food and provide extra nutrients. They are endangered due to overcollection as a delicacy and making into souveniers like ashtrays.

I always find the way flatworms swim mesmerising. Flatworms are very delicate creatures and should always be handed with care.

A group pic with the star attraction of the day: Knobbly Seastar (: They are one of the biggest seastar we have around.

On the way back, we accidentally intrude the territory of this blue flower swimming crab! It was very agressive waving its claws, ready to declare war with us aha. This is a first sight for me! (:

It is one of the few crabs that are swift and agile due to its last pair of paddle-like feet.

This is sandfish sea cucumber is the haisheng that we eat during chinese new year. It breathes using water that is being flushed in and out through its backend. With this constant flow of water, some tiny creatures find the backside of a seacucumber a cosy and safe place to be! I like how one participant liken it to being in a jacuzzi (;

This black phyllid nudibranch cannot be kept in an aquarium. It release toxic substances when dtressed and this kills the entire tank of fishes!

Very soon it was time for us to leave again as the tides come in. A big thank you to upside down jellyfishes for being such attentive and enthusiastic audiences today!

Do check out other guides' posts:

God's wonderful creation