Monday, December 10, 2007

Chek Jawa Intertidal Walk on 9 Dec

I was back at Chek Jawa again last Sunday, so here's a quick summary of some of the things we saw that day.

Since the mass death that happened earlier this year, I've been finding more horseshoe crabs during our guided walks. In fact, I've seen them on almost all the walks I guided so far this year, and once I even saw 3 of them. Have no idea whether this could have anything to do with the mass death or the flood, or could it be just pure coincidence that the horseshoe crabs could have just had a breeding season recently. Anyway, just an observation.

Perhaps due to the rain, we only managed to find one brittle star today, when previously I could easily find several of them stranded on the sand. And this was also the only star we found for the day.

Walking at the edge of the sand bar, I spotted a few pink warty sea cucumbers, breaking the green and brown monotony created by the seagrasses, seaweeds and the sand.

I was very glad to see that the resident bigger-than-your-face carpet anemone was still there despite the heavy rainfall. Hopefully the situation will not worsen and I'm still able to find it the next time I'm here.

As the group moved on, I saw something squeezing out of the sand, and it turned out to be a smooth and slimy sea cucumber. It was translucent with brown spots. Don't think I've seen this species before actually.

There were still plenty of sand dollars around. Some how they didn't seem to be affected as badly by the rain compared to most of the other marine life.

There were lots of drill (a type of snail) egg capsules around too. The yellow ones still have babies drills in them. The eggs turn purple when the larvae hatch.

And we found a tunicate stuck on one of the pillars of the floating pontoon. Like us, tunicates are animals which have a notochord when they are young. But while our notochord eventually develops into our spine, the tunicates lose their notochords as they settle down and mature. Most tunicates are hermaphrodites, meaning they can produce both eggs and sperm. Usually, the eggs are keep inside their body until they hatch, while the sperm is release into the water to fertilise other tunicates.

A pretty purple sponge was also growing on one of the pillars. Mind you, but sponges are animals too! And like other animals, they need to eat too! They do so by sucking in water through the tiny holes on them, and they will pick up any edible particles from the water, then push the filtered water through the big holes. While they look really pretty, please do not handle them with your hands, as most sponges have tiny spikes on them. The spikes will get into your skin and cause skin irritation. Some sponges are known to be toxic too, and may cause numbness or even inflammation.

And here's my group, which I called the mudskippers so that it's easier for me to gather them among the other groups :P

Anyway, despite the rain, it was still a nice walk.

After note: Received an sms from Adelle on Monday, who told me that they saw jungle fowls fighting on the rocky shore, and 2 otters running on the northern sand bar! Wow! The last time I saw an otter was like a year ago at Semakau Landfill! So far on Ubin I've only see otter foot prints. Too bad I had to work on Monday and thus didn't go to help out...

Sigh... Will I have the luck to see the otters during my next walk? I certainly hope so... Though I think chances are pretty slim :(

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