Tuesday, June 5, 2007

Sentosa Walk with Naked Hermit Crabs on 6 June 2007

Seventh Discovery Posting:

(Entry @ 6 June 2007: Error of date entry, the date of walk should be 5 June 2007. =p)

Today was the first guided public walk of the Naked Hermit Crabs@Sentosa! It was a clear morning and the tide was about 0.1m (picture below), so it was really an ideal morning to start the first guided public walk.
Originally, i was assigned to be helping Helen as a co-guide. But due to last minute changes, i was 'promoted' to be the main guide with Kok Sheng helping as a co-guide. And the most 'interesting' fact was that it was the first time i'm a main guide for any inter-tidal walks and it was the first time Kok Sheng was guiding.

Anyway, after an agreement to help one another out, we proceed with our group (Swimming Crabs) to the beach side for the walk.

For the first 'discovery', we actually asked our group members to spot what could they see on the rock walls. And look what they found, a sea slater (picture below).
Discovery Note:
1. They are sometimes called the sea cockroach due to their appearance.
2. They are not insects, they are actually related to crabs and prawns.

3. They are able to live on the land, as they possess ‘pseudo-lungs’ which helps them to breathe air.

As we were about to run off of facts on the sea slater, Ron who was came to check our progress, spotted a flatworm (picture below), second 'discovery'!
Discovery Note:
1. Flatworms has both male and female reproductive systems, so when two flatworms mate. They may fertilise each other!

Third 'discovery' was seen as we headed out towards the waters, a ribbon worm (picture below).
Discovery Note:
1. Some can reach a length of 30 meters with a body diameter of only a few millimeters.
2. They seem to have existed on earth for 500 million years.
3. Usually they feed on scavenges and dead animals.

Fourth 'discovery' was found by our hard working hunter seekers. A brown egg crab (picture below).
Discovery Note:
1. The Brown egg crab is listed among the threatened animals of Singapore due to habitat lost.
2. Egg crabs are highly poisonous and contain toxins which are not destroyed by cooking.
3. Since other animals don't particularly want to eat this crab as it is poisonous, it is slow moving and doesn't really bother to hide.

We were really having a great day, as in a matter of minutes, another animal, this polka-dot nudibranch was spotted. Fifth 'discovery'!
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 hermaphrodites, meaning each slug has both male and female reproductive organs at the same time.
Just like flatworms!

As we approach a rock where a group was gathering, we saw this black object beside the rock. Yucks! It really look like poo. But no! It's a black sea cucumber (picture below) which is the sixth 'discovery'.
Discovery Note:
1. If it is agitated or attacked, it will spill threads that are sticky and hard to remove. So try not to touch it unless you are asking for a 'slimly' time.

Very soon, our hunter seekers bought another animal they found hidden within the waters. A swimming crab (picture below). Hey, isn't it our group name too? Seventh 'discovery'!
Discovery Note:
1. They have paddle-like swimming legs which can rotate like boat propellers to enable them to swim rapidly.
2. They usually swim sideways, but they can also swim backwards and forwards!
3. They possess long pincers armed with sharp spikes to snatch fishes and other fast-moving prey.

As we walked further down the shoreline, we were soon under Fort Siloso. Well, it will be the eighth 'discovery' of the day.
Have you hear about the story that the Singapore Guns were facing the wrong way (south) when the Japanese attacked Singapore from the north during World War II?

Discovery Note (Answer):

1. This is not exactly true. As the British assumed that the defence in the north will be well-covered by Peninsular Malaysia, they build this fort facing south to shore up its defences for the south.
2. Did you know that according to records, most of the forts, including Fort Siloso, actually took part in the battle when the Japanese invaded Singapore.

And as we came to a tidal pool, we saw this colonial anemone in the pool (picture below). This would be ninth 'discovery'.
Discovery Note:
1. They are made up of many small sea anemones. These small sea anemones joins others nearby to form a colony.
2. One form of the most toxic marine poison was discovered in a colonial anemone.

As we started to head back, we noticed that our hunter seekers have really been working hard and their day was really good. They found this copper-banded butterflyfish (picture below) which is to be the tenth 'discovery' of the day.
Discovery Note:
1. They have a large ‘false eye’ on its dorsal fin which fools predators into thinking that it is a big fish.
2. And if a predator does attacks it, the fish unexpectedly swim ‘backwards’.

3. They have a long snout with brush-like teeth to suck up coral polyps and small prey from crevices.

Nearby in a container was a fire worm (picture below) found also by our hunter seekers. Eleventh 'discovery'!
Discovery Note:
1. Fire worms are bristle worms with sharp bristles containing toxins. These bristles which can break easily in your skin can cause extreme pain.
2. They may also release their bristles into the water near them too.

3. So don’t touch fire worms or the water they are in with your naked hands!

Twelfth 'discovery' was a nudibranch (picture below) i've never seen before. Would need help to ID this, anyone? Thanks =)
Discovery Note:
1. Nudibranch is pronounced as 'noo-dee-brank' to rhyme with 'bank'.

And our hunter seekers also managed to find this red egg crab (picture below). Thirteenth 'discovery'! This was a really great day of finds and 'discoveries'!
Discovery Note:
1. You may refer to notes on the brown egg crab for information on this crab.
2. Most Important Point is that this kind of crab is poisonous.

Side Note:
So one day if you were ever stranded on an island with no food, don't EVER catch this crab for food!

As we walked back towards our starting spot, we came across this strangely rock formation constructed by nature (picture below). What could lie beyond where we stood? The only way to know was to walk on...
So this is the infamous cliff (picture below) we have heard about...
As the tide slowly came in, we made our way back towards safe ground. Can you spot the difference between this photo (picture below) with the first?. This was taken about 2 hours after we started the walk.
And of course, with every guided walk, there would be a group photo (picture below). Swimming crabs, say 'fish'! =p
Right after the Naked Hermit crabs did the walk, NSS education group actually did the same walk at the same spot too. This photo (picture below) was taken after they have completed the walk and during a story telling session. Notice how the waters have risen at the beach side.
Lastly, thanks to everyone from 'Swimming Crabs', Kok Sheng for co-guiding (you really did a great job, few more tries i think you can be a main guide) and all the 'Naked Hermit Crabs' for making this morning an enjoyable experience.


koksheng said...

hi july, thanks for ur encouragement!

Glad you were around because many of the things you explained during guiding I dont know and you have made it interactive and fun for the young ones too. Thks for complementing with me to make it a nice experience.

DreamerJuly said...

Yo Kok Sheng,

I mean what i say. You try to do be a guide. okay? =) Just come for more practice sessions and you'll be great.


~ Mantamola ~ said...

The nudi could be flabellina rubrolineata

juanhui said...

Can't *quite tell from the photo but the nudibranch looks like Cuthona sibogae. Take a look at my blog entry and see if it's the same one...