Monday, August 26, 2013

Chek Jawa survey of coral rubble near beacon

We are back at Chek Jawa on a predawn survey and focused on the coral rubble near the Chek Jawa front beacon. We were here last month but the tide was not low enough to document what lies out there.

The tide went out extensively and we were able to survey the coral rubble beyond the beacon itself. So how is this fragile but also richest stretch of Chek Jawa shore doing?

There were quite a number of colourful sponges at the coral rubble but it was just a glimpse of how colourful and thick the marine life was before the mass mortality event in 2007.

Unfortunately, I have never visited Chek Jawa before the mass death. In fact my first visit to Chek Jawa was when we witnessed the mortality event. :( 

From Ria's old photo taken in 2002, you can see that whole coral rubble was covered with thick growths of colourful sponges and other marine organisms.

However, a shot of the beacon area on this trip reveals that the current status is still only a shadow of the glorious past. But recovery is STILL taking place and it is doing so slowly and probably may change into a habitat that is not exactly the same as in the past. Whether it is for better or for worse, time will tell.

I was searching high and low for the Knobbly sea stars (Protoreaster nodosus) and was relieved to find two of them near the front beacon.

Finding these two knobblies is significant for an echinoderm lover like me and makes me believe that marine life is still hanging on tightly on this shore.

A lovely sight on this trip would be these small growths of the Barrel sponges (Xestospongia testudinaria) which were also found in the 2002 photo at the bottom left hand corner. I do hope that many of these will proliferate and grow into larger ones in the future.

Certain stretches of the coral rubble can be quite colourful as they are covered with lots of encrusting sponges, corallimorphs, ascidians, zoanthids and algae.

There are also many Posy sea anemones like what we would find on Pulau Sekudu, which is a stone's throw away.

There are also quite a number of Sea fans or Gorgonians (Order Gorgonacea). Though many of them are yellow and branching, I also came across a short and highly branched pink version and also two of them that are probably Sea whips.

This sea fan has something stuck onto the branches and it seems to be sponges and hydroids.

The seagrass shore near the coral rubble is filled with plenty of Haddon's carpet anemones (Stichodactyla haddoni)!

A purple Haddon's carpet anemone has three of the Kite butterflyfish (Parachaetodon ocellatus) swimming near the tentacles. 

As for this carpet anemone, the colour looks slightly brighter than the common ones that we find on our shores.

These carpet anemones are also found in good numbers at the coral rubble and they are sometimes found together with sponges and soft corals like what you see in this photo.

Not observed previously at Chek Jawa, there are many of these Spiky flowery soft corals (Stereonephthya sp.) that are commonly found on Tuas. 

They are found in different colours such as yellow, orange, blue and sometimes in pink.

There are also a few Pink flowery soft corals (Family Nephtheidae) at the coral rubble.

And if you were to pay a closer look at the tentacles, you would realize that there are commensals such as Tiny colourful brittle stars (Ophiothela danae) that live on these soft corals.

Also another type of soft coral, I only saw one Ball flowery soft coral though. It has a commensal snapping shrimp that I didn't notice until I processed the photos back at home.

A good sign of recovery would be many small and medium-sized colonies of the boulder-shaped Pore hard corals (Porites sp.).

There was even a Carpet eel blenny (Congrogadus subducens) lurking inside the crevice of the hard coral!

I also came across a dark green version of the Pore hard coral which is quite large as compared to the others on the coral rubble.

The polyps of these types of hard corals are very small and these also explains for the short tentacles that stick out like star-like structures.

I'm not too sure what this colony of hard coral is.... could it also be the pore hard coral? Or is it the Neat hexa corals (Pseudosiderastrea tayami)?

I also saw the Boulder sandpaper coral (Psammocora sp.) on the edge of the coral rubble. This colony is quite large!

There was another one that was found beside a carpet anemone. Though the splashy waves made it hard to photograph, it was a relief that the waters are quite clear when the tide was at its minimum.

There are small clumps of the Tape seagrass (Enhalus acoroides) at the deeper ends though the blades have been "chomped off". The tape seagrass is seldom seen on Chek Jawa.

Lots of echinoderm reside on the shores of Chek Jawa such as this six-armed version of the Eight-armed sand star (Luidia maculata).

There were also two of the blue and black Feather stars (Order Comatulida) which looks elegant when their arms are extended outwards.

Though sighted at Sekudu a few times on previous trips, this is my first sighting of the Long black sea cucumber (Holothuria leucospilota) on Chek Jawa. These sea cucumbers are very commonly found on rocky shores of the South.

Ria shared with me her find of this Synaptic sea cucumber that was found coiled around the yellow sponges. Apparently, she saw quite a number of them which I was oblivious of their presence when documenting the coral rubble.

We also took time to look at what lies underneath the House Number 1 jetty on a super low spring tide. This is a first time for me and I was glad to see colourful encrustations and branching sponges! There were many Biscuit stars (Goniodiscaster scaber) and sea fans as well!

A special find underneath the jetty would be this pretty Purple-spotted yellow flatworm (Pseudoceros laingensis).

The shores of Chek Jawa are still very much alive and sometimes all we need to do is to sacrifice our sleep to survey the shore at super low spring tides which normally take place at super unearthly hours. This trip started near 4am! 

Thank you Nparks for giving us the permission to visit the shore. Chek Jawa Wetlands is out of bounds to visitors going down but we can still visit this precious location through the boardwalks.  

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.