Thursday, August 16, 2007

Monitoring Sand Stars at Chek Jawa

How difficult can it be to take a photo of a sand star?

Today, a gang of nature volunteers were down at Chek Jawa to help Kok Sheng with his Chek Jawa Mortality and Recovery Project. My task was to monitor the sand star (Astropecten sp.) population at Chek Jawa.

In case you have not seen a sand star before, this is how it looks like.

When Kok Sheng briefed me on my task, it didn't sound too difficult actually. I was supposed to find the sand star population, get the GPS readings for the boundary of the population, take down the radius of 15 sand stars, and take photos of them.

Doesn't sound too difficult right? And that's what I though too, until I started doing it.

Just imagine having a torch in your mouth, a clip board and a camera on your left hand, and a pen and a ruler on your right hand.

Finding the sand star was not a problem, but trying to measure the radius of something which kept sliding away or burrowing into the sand was a a big headache. And when I finally finished measuring the radius, and tried to take a photo using the ruler for scale, this was what I got:

It had gone too far away from the ruler! Just imagine, you put it down next to the ruler, lift up your camera, focus, shoot. And oops, it has run away. Catch it, put it down next to the ruler again, shoot.

Oops, it has burrowed.

Ahem... Seems like it's not exactly as easy as I thought it will be.

Or rather, perhaps, I hadn't found the easier way yet?

After measuring 15 sand stars from the first population, I finally discovered the secret of measuring and taking photos of sand stars...

Place them on moist but compact sand.

If the sand is too wet or under water, the sand star can burrow or slide away easily.

If the sand is too dry, sand particles will stick on the sand star and you can't get a good picture.

Moist but compact sand - too hard to burrow, no water for it to slide away quickly, and sand won't stick onto it. Haha, perfect! Can even take two at one go!

So now, the only remaining problem was the rising tide!

So after I was done with the first population, off I went searching for another one at the northern sand bar.

With the waves splashing against my butt, this was the last photo I took of the sand stars before they disappeared with the rising tide.

Sorry Kok Sheng, no time, and had to take everything together.

But anyway, while I was monitoring the sand stars, I came across a few other interesting animals along the way.

Sometime after the great flood, lots of brittle stars started appearing at Chek Jawa.

Why the sudden jump in population? Had there been an increase in food sources, or did the flood wipe out their predators? In fact, not just the brittle star, the huge sand star population was also observed sometime after the flood.

The peacock anemones were pretty as usual. This one had a ring of tube worms surrounding it.

I also found several juvenile sandfish sea cucumber!

There are also many whelks carrying little sea anemones on their back.

And in one of the tidal pool was this cute little seahorse!

There are also lots of juvenile carpet anemones, which Ria and some others were monitoring today.

As we were leaving, we were greeted by lovely flowers of the delek air!

What a great way to end a wonderful trip, don't you think so? :)

See also:
- Chek Jawa Monitoring trip at CJ Project Blog
- Monitoring Chek Jawa's recovery at Wildfilms Blog


Liana said...

so funny the sand stars. looks like everyone did a great job, kok sheng should be so proud :p wish i could have been there la

tHE tiDE cHAsER said...

Heh heh. Great job or not will have to wait till KS see my photos... :P

Must knock YC's head for taking your place :)