Semakau Walk on 28 Aug

Haven't blog for a long time! Am quite busy with school etc. Hopefullyyyyy i'll get more time to blog about all the places that i went after this semester ends :D

Anyway, finally went to Semakau today again! :D But instead of guiding, i went as a participant with NUS High to listen to other people guide :D haha. My group was the Seagrass group! (: And our guide today was mindy!

As usual, as it was a morning walk, we had to walk to the intertidal area. The weather today was great! It was quite windy and cooling and i think everyone enjoyed the walk to the forest (:

The best reward from morning walks is the beautiful sunrise (:

Saw this plant beside the road along the rock barn. Never noticed it during the previous trips. Did it just grew recently? Or was i not observant enough? haha. Not sure what this plant is though.

We walked through a patch of secondary forest and reached the intertidal area. To get rid of the irritating mosquitoes, we headed out for the mangroves first.

Here's mindy telling the group about the mangroves! As these plants live under harsh conditions, they have several adaptations which enable them to survive better. For example, the Rhizophora species have prop roots which helps them to stabilize themselves on the soft ground. They also have waxy leaves to reduce water loss due to the high salinity level and the high amounts of sea spray that they get.

And of course, they have special adaptations for reproduction too. Instead of just letting their seeds germinate themselves in the harsh conditions, the seedlings, called propagules, are germinated on the parent tree. When it is more matured and ready to face the real challenge, it will drop down from the parent tree and get carried away by the current, and hopefully it will land somewhere suitable for growing.

When we look down at the mudflat, we often see trails created by these Creeper Snails. The longer the trails, the longer the tide has been out.

As we walked along the side of the forest, we saw this Sea Lime (Ximenia americana). Unfortunately, it wasn't flowering nor fruiting. During the one of the previous trips, i tried eating the fruits of the Mangrove Lime for the first time, and it tasted quite nice! :D

Next, we saw a Sea Hibuscus (Talipariti tiliaceus). This is also a coastal plant, with distinctive heart-shaped leaves. The yellow flower will open in the morning, and as the day gradually passes, the colour of the flower changes to pink, and then wither and dries up when the sun goes down.

On the same plant, there were quite a few juvenile Cotton Stainer Bugs (Dysdercus sp.). Interestingly, these Cotton Stainer Bugs feed on the seeds of this plant and are not able to survive on other plants.

As we headed out, we walked past another mangrove plant (Avicennia alba), which has pencil roots instead of prop roots like the Rhizophora species.

On the rocks, there were many Oysters (Family Ostreidae) growing.Oysters are sessile animals usually encrusted on rocky surfaces and filter feeds to get food from the surrounding water. During low tide, it will close up its shell to prevent water loss and protect itself from its predators.

Near the roots of a Bakau Tree, there were many Fiddler Crabs (Uca annulipes) scrambling around. The ones with a big claw are the male Fiddler Crabs. The big claw helps to attract the attention of the females and ''tells'' the females that 'LOOK! I have a big claw = I very powerful = I can protect you'. So, the bigger the claw, the sexier it is. However, it also handicaps the males as it cannot use the gigantic claw to feed itself and also makes itself more visible to the predators.

In the pools of water, we saw this Blue Striped Hermit Crab (Clibanarius longitarsus) in a telescopium shell! As hermit crabs are not true crabs, they have a soft abdomen which requires them to have extra protection. As the hermit crabs grow bigger, they will need to seek for a bigger shell to stay in. However, if it can't find a larger shell, instead of growing bigger, the hermit crab will shrink! :O Hence, it is important that we should not pick up shells whenever we visit the beach. Quoting Mindy, some people may have the mentality that it's okay to just bring home ONE shell because it is just ONE shell. Imagine everyone in Singapore has the same kind of mindset, then 4 million shells will be gone! And the poor hermit crabs will shrink, or have to walk around the shores naked.. ):

On almost every trip to Semakau, this is quite a common sight. Although this may look like some defecate of some sort of animals, it is actually an Acorn Worm (Family Enteropneusta) cast! The worm is buried underneath the sand, and as it moves deeper into the sand, it swallows the sand and process them, then passing the processed sand out from the other end of its body, to the surface thus forming the cast.

Here's a picture of the Victoria boys near the Seagrass meadow.

And our dearest Hunter-Seekers at work! (:

One of the girls in my group spotted this in one of the pools of water. I thought it was quite cool as it resembles a hand showing 4 fingers, which reminded me of the 4 points that all the guides will stress on before we go for an intertidal walk.
1. Always walk behind the guide as the guide will know which is the safest and best route to walk.
2. Always walk in a single file to minimize the damage done to the living things in the area.
3. Never touch things unless the guide says so, as there are many animals like the anemones with stinging tentacles and may sting quite badly when you touch them.
4. Never remove your shoes at any time during the walk as it is very dangerous to walk barefooted on the shores.

Back to the organisms, this was the first pair of Sand-sifting Sea Stars (Archaster typicus) in the pseudo-copulation position. It is said that these sea stars staying in this position for 3 months before they release their eggs and sperms into the surrounding water will help to increase the chance of external fertilization. It is great to see these sea stars reproducing! (:

As we walked on, we were greeted by a Sponge invasion. Sponges are very simple animals that comes in many different kinds of colours, shapes and sizes. Sponges in real life do not look like SpongeBob at all. In fact, i've never seen a square Sponge before! Hahaha.

The hunter seekers found us a Synaptid Sea Cucumber (Family Synaptidae). Sea Cucumbers have oral tentacles that they will extend to grab food particles into its mouth when it is submerged in water. As this species of Sea Cucumber has very thin walls, we should not touch them as they may be stressed up and disintegrate!

At the same area, we saw not one, but TWO! Dragonfish Sea Cucumber (Stichopus horrens). Unlike us, Sea Cucumbers are invertebrates, thus, when they are out of water, it may look like it's 'melted'. This also enables them to camouflage better in its surroundings.

Then, we headed for the Death Zone! If you look closely, you'll see a walking trail amongst the Seagrass. The Death Zone was formed after numerous trips. To minimize the damage done to the Seagrass meadow, we will always stick to one path, thus stressing the importance of walking in a single file.

At the side of the trail, i saw this very beautiful Stonefish Sea Cucumber (Actinopyga lecanora).

When we reached the sandy area, we saw this Cushion Star (Culcita novaeguineae). Just like other Echinoderms, including sea cucumbers, they have a penta-radial symmetry which can be seen clearly with the 5 rows of tube feet.

We also saw this Sandfish Sea Cucumber (Holothuria scabra). This is the species that we usually eat in the Chinese restaurants. However, it needs to be properly processed before it is edible.

Amongst the Seagrass, we saw this Gigantic Anemone (Stichodactyla gigantea). This is one animal that we shouldn't touch as these anemones have stinging cells in their tentacles that may sting your fingers if you touch them.

As we moved on, we saw this ultra long drift net just beside the seagrass. It feels very depressing to see drift nets on our shores as it causes detrimental effects to the animals like fishes and crabs. 

Many fishes were found trapped and dead in these nets..

The possession of these drift nets is actually illegal in Singapore. Despite many drift nets found and many innocent animals killed, the authorities don't seem to be doing anything about it. Hopefully the drift nets will be removed soon so that animals will not be killed by it anymore.

Moving on, we saw two Noble Volutes (Cymbiola nobilis).  Although they have very pretty shells, they are actually very fierce predators that can wrap their muscular foot around their preys to suffocate them!

Beside the Noble Volutes, we saw this Sand Collar. It is the eggs of the Moon Snails. When the eggs hatch into little Moon Snails, the Sand Collar disintegrates and disappears. Signs of reproduction tells us that the animals are doing well! (:

This looks like a.. hybrid? Haha it doesn't look like the normal Knobbly Sea Stars that we usually see.

The Knobbly Sea Stars (Protoreaster nodosus) are the iconic animals of Semakau. On every visit, I'll hope to see some of the knobblies to make my day. Just learnt from a shrimp expert that some tiny tiny shrimps may live on the knobblies! Shall try to look out for them next time.

We also saw a dead Scallop (Comptopallium radula). The Scallop has a special way of moving which i think is quite cute :D As they are bivalves, they have a two-part shell and to move, they will flap their shells and eject water from their mantle cavity.

As we moved further out, we saw another Stonefish Sea Cucumber (Actinopyga lecanora)..

and 2 more Cushion Stars (Culcita novaeguineae)! Happy to see the yellow one again :D it seems to be doing well and growing bigger everytime we see it! (:

It seems to be a Echinoderms day as we saw 4 different kinds of Sea Cucumbers and 3 different kinds of Sea Stars! (: A group shot of the juniors with our awesome guide :D Hope everyone enjoyed themselves today, and jiayou to the juniors who are supposed to complete their assignment! :P