Saturday, July 27, 2013

Chek Jawa coral rubble survey after 4 years

It has been a long 4 years since I have last surveyed the coral rubble of Chek Jawa. Thanks to NParks for permission and support for us to carry out low spring tide surveys of Chek Jawa, we were able to document the shore on this 1 am trip last Sunday morning.

The coral rubble area is the most delicate and also richest part of the intertidal shores of Chek Jawa. The most prominent landmark on the coral rubble would be the Chek Jawa front beacon that directs ships plying the Johor Straits between Ubin and mainland Singapore.
I found the large Pink flowery soft coral (Family Nephtheidae) below the beacon and couldn't really find the other usual other reefy organisms such as the Boulder Pore corals (Porites sp.) that can be found on the coral rubble. There is also a sea fan below the beacon but it looks half dead. I am guessing that it is because the water was not low enough for us to look at the area properly.

Thankfully, there are still many small patches of sponges on the higher shores of the coral rubble. They come in all sorts of forms and colours.

Surprisingly on the high shores, there is a large patch of the Blue jorunna sponge (Neopetrosia sp.) and I took this photo with Ivan in it so that you can tell its size.

With sponges, there are many more slugs and nudibranch that would also naturally be found in the vicinity. We found many types of sea slugs including a couple of the Lined chromodoris nudibranch (Chromodoris lineolata).

Chay Hoon found the pretty Hypselodoris kanga nudibranch and this is my second time seeing it! One of the identifying features of this slug is that it has yellow dots on its flowery gills.

This is a tiny yellowish-orange slug that only Chay Hoon can find! It has specks of white dots on its body and is probably a Doriopsilla sp.

This unassuming Black prickly nudibranch (Atagema intecta) that looks like a lump of black stuff can be quite well camouflaged as they are usually found among rocks and rubble.

I do not spot tiny slugs very well unless I happen to squat down and start looking around. That was how this Emerald Stiliger slug (Stiliger smaragdinus) was found. This slug is usually found among the Caulerpa seaweed.

Other than the slugs, there were also many flatworms found on the coral rubble! It ranges from the Red-tipped flatworm (Pseudoceros bifurcus), Blue-spotted flatworm (Pseudoceros indicus) and also the Purple-spotted yellow flatworm (Pseudoceros laingensis).

Ivan found this Brown striped flatworm (Pseudobiceros gratus) that we don't often see on northern shores.

Though the Fine-lined flatworms are not commonly found on our northern reefs, it seems that this flatworm is in season as we saw quite a number of them.

On the pillar of the boardwalk during the outgoing tide, I was intrigued by this fish. After a close look, it does resemble the blenny that we saw at one of the sea walls of East Coast in the past.

As the tide went out, we stumbled upon this Pencil squid (Family Loliginidae) that is usually found at night such as this predawn trip. It was quite huge!

On the rocky shore, there are speckles of colours from sponges, fan worms and crabs.

Something cute found on the tube of the fan worm would be this tiny crab that Pei Yan spotted. Can you see it in this photo?

The patch of seagrass near the coral rubble and House Number 1 has lots and lots of the Haddon's carpet anemones (Stichodactyla haddoni)! Good to see that they are thriving well.

Here's another photo of the huge anemones and I missed the tiny kite butterflyfish (not obvious in this photo) on the bright green anemone until I processed this photo at home.

On the seagrass, there was an explosion of many baby Swimming anemones (Boloceroides mcmurrichi)!

There were so much of these baby sea anemones that they were even found on the surface of the Coin seaweeds (Halimeda sp.).

I saw two of the Blue-spotted fantail rays (Taeniura lymma) that are commonly found on our southern reefs.

Now over to my most favourite group and that would be the sea stars of Chek Jawa. The coral rubble was still very starry and I managed to find a juvenile Knobbly sea star (Protoreaster nodosus) among the seagrass.

Later on, I also found the six-armed version of the Eight-armed sand star (Luidia maculata). The rest of the team also saw another one.

There were quite a number of the other types of sea stars such as the Biscuit stars (Goniodiscaster scaber) and Cake sea stars (Anthenea aspera) that we decided to put some together for this family shot haha!

It's been a while since I have last seen this Scaly sea star (Nepanthia belcheri).

The underside of this sea star is prettier in red and pink!

As for the cake sea stars, Ivan found this large individual with a lovely pattern of brown dark green and light green.

Here's another sea star of the same species but in pink! I simply love the cake sea stars for their different patterns and colours. :)

On top of the many sea stars shown earlier, the Spiny sea star (Gymnanthenea laevis) was with orange tips on its arms was also sighted. Good to see a healthy representation of the sea stars on the coral rubble.

As the tide returns, we went to the seagrass lagoon and sand bar to have a quick look and the Sand stars (Astropecten sp.) were out in full force.

There were stretches where many Haddon's carpet anemones (Stichodactyla haddoni) are found on the sand bar. 

AND also the seagrass meadow!

There are also many Cerianthids (Order Ceriantharia) that look like flowers of the shore.

The Garlic bread sea cucumbers (Holothuria scabra) are active at night and I saw far lot more of these cucumbers on Chek Jawa than on Changi. This is probably because that this shore is far more inaccessible and that no one is supposed to go down to the shores as access is restricted.

Unfortunately, there are still threats on Chek Jawa such as illegal fishing, poaching and laying of drift nets. We found a drift net that stretches almost half of the length of Chek Jawa and it entangles and traps many marine life alive.

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