Sunday, January 17, 2010

3 years after the mass mortality event

It's January 16th of 2010 and almost exactly three years after the gruelsome mass mortality event that occured in Chek Jawa. Joining Teamseagrass on the shore, I went to have a quick short look at how is the shore doing for now and whether is Chek Jawa hit by the impact of the 'Dead fish zone' at Pulau Ubin.

The relative positions of the sandbar and the seagrass always seem to be rather dynamic and whenever I visit Chek Jawa after many months (my last visit was Aug 2009), it seems to have changed a bit.

This time, there were many of the Noble volutes (Cymbiola nobilis) laying eggs. But I thought I should look out for the soft bodied animals to see if low salinity has impacted them. A week ago, my friend Pamela mentioned that the salinity at Pasir Ris was 16 ppt.

The only sea star species I came across is the sand star (Astropecten indicus). Did not sight the common sea stars (Archaster typicus) but they are still around as they have been seen during CJ guided walks.

Instead, I saw a wide variety of sea cucumbers! Here's the list of them...

This is the Pink warty sea cucumber (Cercodemas anceps).

Thorny sea cucumber (Colochirus quadrangularis).

This is the Smooth sea cucumber that is usually only found buried in the sand.

There were quite a number of the large Garlic bread sea cucumbers (Holothuria scabra) that seem to be settling well for some time already.

Last but not least, this Purple sea cucumber (Family Cucumariidae) that we usually see on northern shores.

Glad that the sea cucumbers are fine! That's a good sign.

As usual, the sand dollars are teeming certain parts of the sand bars, especiall the north. They are usually covered with a thin layer of sand.

And here's a closer look at this Cake sand dollar (Arachnoides placenta).

One of my task is to find the return of the Button snails (Umbonium vestiarum). They have been missing for 1.5 years! And I'm so happy to find them back in big patches on the north. Yay!

How about the Carpet anemones (Stichodactyla haddoni)? Almost all of them look fine with no signs of bleaching. Some of them settled well among the seagrasses.

A pleasant surprise will be the north shore where many of the carpet anemones have colonized the sandy area. Can you find all five of them together in this photo?

Here's one of the prettier carpet anemone.

My impression of the number of Peacock anemones (Order Ceriantharia) remains the same though. I didn't really see an increase though it was just a general feel.

That's about all for the animals that I usually look out for to monitor. But of course, Chek Jawa is alive and there's other creatures that I found along the way.

Like this bunch of cuttlefish eggs in black.

I found these weird orange blobs on the seagrass blades. Are they ascidians or egg masses of some animals?

It was interesting to once again come across another of the giant-sized Mud crab (Scylla sp.) on the shore. I didn't dare to get too close as it was too big and scary looking.

An interesting find will be this moon snail that I don't think I have ever seen before alive. It has a brownish shell.

And here's the underside. Hope someone can provide the id.

Whereas James found a solefish that I can't really tell its exact identification too.

I was thrilled to find this featherstar clinging on the knobbly sea fans on the pillar of the floating pontoon. Have not seen featherstars at Chek Jawa for a long time!

The legs of the CJ boardwalk is teeming with sponges and ascidians.

And below some of them, once again, are many egg-laying noble volutes. Haha. Can you spot the cowrie at the pillar leg too?

That's all for a short one-hour check out. Glad to know Chek Jawa is recovering well, with no signs of being impacted by the dead fish zone or low salinity. :-)


Joe Lai said...

Keep up the great effort and a happy new year! Cheers : )

Kok Sheng said...

Thanks Joe! Happy new year to you too!

Unknown said...

Hi there, i'm a reporter from Sph following up on the oil spill. Wondering if I could find out more info from you about Chek Jawa please? You can contact me at kohsm [at]sph[dot]com[dot]sg

Appreciate your help. Thanks!