Sunday, March 23, 2008

Discovery @ Semakau on 21 March 2008

Fifty Second Discovery Posting:

It was Good Friday (21 March 2008) and a batch of us were out on Semakau with Dr Dan and his group of students. Although this was a trip especially for Dr Dan's students who were from Duke University to explore our shores, i didn't really play a good host to them as i had other ideas on mind for going to Semakau =P.

Well, I was hoping to locate juvenile knobbly sea stars (Protoreaster nodosus), wanted to do it because CK couldn't find any of them during the last exploration trip and my mini study on them was still on.

As i was walking away and probably much ahead of others, i didn't manage to spot as much things as them, probably because i only have one pair of eyes. =P

But after about 20 minutes and not much luck in spotting anything, I saw my 'goal' of the trip. YES! First 'discovery' (picture below)!
Discovery Note:
1. This knobbly sea star was probably about 10cm in length for each limb. About one time bigger than the juvenile knobbly we saw last time when we were on Semakau.

Maybe my luck wasn't that bad after all, i thought, so with my hopes higher, i moved on.

And shortly after, i came across the second 'discovery', a synaptid sea cucumber (picture below).
A closer look near its mouth (picture below).
Discovery Note:
1. It has no tube feet except for highly modified ones that form the oral tentacles.
2. It has a very thin, delicate body wall that feels sticky to touch. The stickiness is not due to mucus or other adhesive, but to other hundreds of tiny, anchor-shaped ossicles located in the skin.

We were really lucky to have a almost clear sky on the day. Because if it's clear, we will get to see the sunset! Here's the first of the set of sunset photos i took on the day (picture below).
As i continued to look around amongst an area of seagrass, i saw a stir of the sand nearby and a closer look proved to be the third 'discovery', a coastal horseshoe crab (picture below)Discovery Note:
1. Horseshoe crabs have known to 'roam' the earth since days even before the dinosaurs was around, so scientists calls them 'living fossils'.
2. Although they are called horseshoe crabs, they are not related to crabs. They are actually more related to spiders and scorpions.
3. There are two types of horseshoes crabs which we can find in Singapore, the mangrove one (circular tail) and the coastal one (the trianglar tail)
4. The tail is not venomous and is not used as a weapon. It is merely used as a lever to right itself if it is overturned. If you see an upside down horseshoe crab struggling with its tail waving around, do give it a helping hand. It will not hurt you.

5. The blood of the horseshoe crab is blue, as it is copper-based.
6. Their blood is able to clot easily when it detects bacteria, so their blood was harvested for these purposes until a team from NUS's department of Zoology has cloned a substance to replace using horseshoe crab's blood. Read more about it here.

And just not far away from what i saw the horseshoe crab was some round shapes on the sand. Oh, sand dollars. (picture below
) And this is fourth 'discovery'.Discovery Note:
1. Living sand dollars are coated in fine, harmless spines that made them very velvety.
2. The spines are movable and are used to dig into the sand or move around.
3. The dense layer of spines also helps to keep off sand and silt so there is a flow of oxygenated water across the body.

As the sun continued its descent down to the horizon, i continued my photo taking of its movement (picture below).
And as i went on walking around the seagrass area, i spot this mosaic crab (picture below), fifth 'discovery'.Discovery Note:
1. This is one of the most poisonous crab in Singapore.
2. Thus, I give the strongest advice not to eat this. =)

The beautiful sunset again (picture below).
As I rejoined the main group, CH cried out, 'Knobbly'. And i not wanting to miss another chance to see another knobbly went over and it was another knobbly sea star (picture below) which was similar in size to the one i saw earlier. What luck!Finally, a photo of the full moon from the shores we were at (picture below). PY commented at the sides that this didn't looked like we were on Singapore and i agreed totally. =)Lastly (really the last), it's thanks again everyone!

a) More about the trip on Wildfilms.
b) Check out the seahorse they saw on Colourful Clouds.
c) A very very tiny cowry on manta's blog.

Monday, March 10, 2008

Semakau Inter-Tidal Walk on 9 March 2008

Fifty First Discovery Posting

Singapore. An island with one of the most busy ports in the world (picture below).
It is also our fortune to be able to view reefs within an hour of boat ride from our city at our southern islands. Yes, we have coral reefs in Singapore! Read more about them here.

Yesterday, we were on Pulau Semakau ,one of these special southern islands, where we can view coral reefs without having to dive (picture below). Do you know that this island is also first offshore landfill island and last landfill in Singapore? Read more about it here.
My job again was a hunter seeker, together with CH, Robert and HW. Basically, we are in charged of finding the interesting flora and fauna for our visitors. Here's us moving past the forest trail(picture below). Upon exiting the forest trail, Robert spotted a net off the side. And a closer look brought a shock for us, as there were two trapped horseshoe crabs which were alive! Immediately, we sprung into action and released the first 'discoveries' from the net (picture below). Discovery Note:
1. Horseshoe crabs have known to 'roam' the earth since days even before the dinosaurs was around, so scientists calls them 'living fossils'.
2. Although they are called horseshoe crabs, they are not related to crabs but more related to spiders and scorpions.
3. There are two types of horseshoes crabs which we can find in Singapore, the mangrove one (circular tail) and the coastal one (the triangular tail)
4. The tail is not venomous and is not used as a weapon. It is merely used as a lever to right itself if it is overturned. If you see an upside down horseshoe crab struggling with its tail waving around, do give it a helping hand. It will not hurt you.

After the rescue 'mission', we proceed to start our seeking. And very soon, we managed to find the resident gigantic carpet anemone (picture below), second 'discovery'.
Discovery Note:
1. For self defence and preying purposes, they have stinging cells in their tentacles which will release or 'shoot' small 'needles' when upon contact. So I won't really advise you to touch them although our skin might be 'thicker' than most marine creatures. This is to prevent you from getting stung.
2. They lack an anus, so they split out any indigestible food through its mouth.

Third 'discovery' is a flatworm (picture below).
Discovery Note:
1. Flatworms are hermaphrodite, which means a flatworm has both the male and female sex organs.
2. And certain species of flatworms engage in penis fencing, in which two individuals fight, trying to pierce the skin of the other with their penises; the first to succeed inseminates the other, which must then carry and nourish the eggs.

Fourth 'discovery' is something that looks a little like a flatworm. But it's not, this is a kind of sea slug, a Chromodoris nudibranch (picture below)Discovery Note:
1. 'Nudibranch' means 'naked gills'. The name comes from the flower-like gills found on the back of many nudibranchs. These nudibranchs use the gills to breathe.
2. Nudibranchs are related to snails. Little baby nudibranchs are born with shells, but they lose them when they become adults.
3. Most nudibranchs are carnivores, they eat immobile or small, slow-moving prey. Examples are sponges, ascidians, hard corals, soft corals, sea anemones etc.

Fifth and sixth 'discoveries' are sea cucumbers, the one above is the ocellated sea cucumber while the one below is the sandfish sea cucumber (picture below).
Discovery Note:
The popular Chinese name for sea cucumber is haishen, which means, roughly, ginseng of the sea.
Being related to the sea stars, sea cucumbers have a soft, wormlike body and range from a few centimeters to 90 centimeters in length.
Unlike the sea star, however, they have no arms but use a cluster of tube-like feet around their mouth to gather food.
To repel predators or when stressed, a sea cucumber might expel their innards or ‘vomit’. And if too much of their innards are expelled, they might die off as a result.
The sandfish sea cucumber is the species of sea cucumber which people consume. But they contain toxins, so it must be properly prepared before consumption.

Now after finding a number of interesting things, it was time to look for the icon of the walk, the knobbly sea star. After some hard work from us, here is seventh 'discovery' (picture below).
Discovery Note:
1. They get their name from the knobs they have.
2. Although most of them are mostly red or orange in colour, beige or brown coloured knobbly sea stars have been spotted before also.
3. Can you believe that a knobbly seastar might be larger than your face? It’s about 30cm across! (look at the pictures below to get an idea)

After managing to find the icon, i decided to take a breather and take photos of the groups coming over to have their group photo taken with our icon. Here's ST and HK's group in the progress of taking the photo (picture below)
PY's group posing with the knobbly sea star (picture below)And of cos the beautiful sunset... (picture below)Finally, thanks to everyone for making this trip another wonderful and joyful one!

a) Dr. Yaacob Ibrahim, Minister for Environment and Water Resources, also participated with us for this trip. Read more about it at Nature Scouter's blog.
b) Also check out what did Nature Scouter aka SJ saw during the trip.
c) Read Tidechaser's experience of guiding Dr. Yaacob.
d) And of course Manta's experience.

Sunday, March 9, 2008

Semakau Inter-Tidal Walk on 8 March 2008

Discovery Posting Number Fifty!

For the second public walk of the year 2008, i was assigned to be one of the hunter seekers, which means i have to find interesting things and mark them out for the guides, which also equates to if i can't find anything, i will be very stressed... Anyway, today, CH was together with me on this 'job'.

Although this 'job' is stressful in a way, it does have its benefits, we get to have a bit of time (it's really not much) to take photos, here's a photo of part of the inter-tidal area of Semakau (picture below)
And be the first to cross the seagrass lagoon and enjoy the view of the clear waters (picture below).
And of course the feeling of finding something interesting is really great! Here's 'first' discovery', an upside down jellyfish (picture below)
Discovery Note:
1. Its name is thus because you will usually find this jellyfish upside down.
2. The upside down position allows zooxanthellae which lives on the underside of the jellyfish to get sunlight so they can photosynthesize.
3. And the zooxanthellae when photosynthesizing shares its food with the jellyfish, while the jellyfish gives the zooxanthellae a place to call home.
4. So they have a symbiotic relationship.

Second 'discovery' should be a juvenile noble volute found by CH(picture below).
Discovery Note:
1. Volutes are carnivorous.
2. They prey on bivalves, enveloping the victim completely with their foot forcing the bivalve to finally open from exhaustion and lack of oxygen.
3. They can grow to more than 20cm and used to be common but now threaten due to 'harvesting' from humans and habitat lost.
So it's really great to see a 'young' one!

Third 'discovery' should be a great egret (picture below) which was perching at the reef edge area (picture below).
Discovery Note (information from Sungei Buloh online guidesheet):
1. Great Egrets feed on mostly fish, but will also take amphibians (frogs), aquatic invertebrates (insects, crayfish), and reptiles (snakes).
Great Egrets are skilled hunters.
3. They stalk the shallow waters or mud flats, walking slowly or quickly with their strong neck coiled at ready. And when suitable prey is spotted they straighten out the neck, to instantly snatch the prey. When fishing, they may tilt their heads to one side, possibly to avoid the glare of the sun's reflection on the water.
Great Egrets may also use their feet to stir up the water and scare up a victim.
5. For more information on the great egret, click here.

As I walked around to find more interesting marine creatures, CH spot a blue-spotted stingray trapped in a net, and with the help of Shawn (NEA staff), it was freed. Fourth 'discovery'.
Discovery Note:
1. The position of the eyes allows the blue spot stingray to see almost behind it.
2. The gills and mouth are found on the underside of the body.
3. The blue spot stingray doesn't really have teeth—instead, the mouth is outfitted with two food-crushing plates.
4. Rays dart away when they sense trouble approaching. When caught off guard, these fish fend off predators with a flick of the tail, which is equipped with two venomous spines. Since its tail is so long, the blue spot stingray can even strike at animals directly in front of it.
5. The large tail spine of the blue spot stingray is dangerous and even deadly. The barbs in the tail are so large; people have bled to death from a sting.

In the end, we managed to find quite a number of marine flora and fauna for the visitors. However, in the view that many others might blog about this trip, I'll leave the job to them. Or you could say I'm a bit lazy. =P

a) See more creatures on Tidechaser's blog entry.
b) Read more about the anemone shrimp on Urban Forest.

Anyway, thanks to all again for this wonderful trip to a favourite place. =)