14 February 2010

Chek Jawa check up with Dr Dan

Another blue sky hot hot day out, this time on Chek Jawa with Dr Dan and Mike and the students from Duke University.
The Duke University comes every year to do a module studying various aspects of environmental issues in Singapore. Dr Dan has been a strong advocate of Chek Jawa and is involved in among (many) others, projects such as Kok Sheng's study of Chek Jawa after the mass deaths in 2007.

What a nice surprise that Sivasothi and Airani could join us for the trip! Yay! Siva is also part of Kok Sheng's Chek Jawa project and of course, a major force in efforts at Chek Jawa prior to deferment of reclamation. Siva will also be giving the students a session about this and other issues later on in the programme.
It was also fabulous to have Chay Hoon with us to guide the students.
The tide was still a little high when we first arrived, so we had a little look at the top of the Jejawi Tower. Which gives a good panoramic view of the surrounding area and the vegetation types: mangroves, secondary forest and coastal forest. And also a nice spot for a group photo.
We stop for a while on the boardwalk to have a look at the intriguing fiddler crabs (Uca sp.). We learnt from Dr Dan that the females are NOT attracted to JUST the giant pincer of the male fiddler crab. While waving the giant pincer about can help gain the female's attention and intimidate rivals, the female makes her final selection based on the quality of the burrow he has dug out. Dr Dan also explains that the male crabs dig out the burrow with his small pincer and his legs! Wow, I didn't know that!
Siva also give a quick introduction to mangroves using the lovely specimens of trees growing nearby. He says it's easier to learn about mangroves (compared to rainforests) because only a few species can do well in the tough intertidal conditions. Haha, yes, I must agree! Although mangrove plants are quite fascinating in their own right.
It was a breezy blue day as we quickly walked the boardwalk. The seagrasses are lush and doing well. And the big Sea lettuce (Ulva sp.) bloom seems to be tapering off.
We spot lots of large cute Gold-spotted mudskippers (Periophthalmus chrysospilos) from the boardwalk!
Then Paul of NParks kindly brought us through to the ladder! Many thanks also to Annabelle for arranging the trip, we're so sorry she couldn't join us.
The tide was a little high as we head for the northern shore. Dr Dan is doing the study route to check out the situation for an upcoming paper on Chek Jawa.
We find all kinds of interesting animals, such as several large Noble volutes (Cymbiola nobilis).
Dr Dan is interested in the egg capsules that these snails create. For the possible novel glues that they use. Dr Dan was involved in the ground-breaking study on barnacle glue! Dr Dan takes a closer look at this egg capsule that is empty.
Chay Hoon finds several Sand stars (Astropecten sp.), both the Painted and Plain ones.
Dr Dan finds a flower crab (Portunus pelagicus) and shares about it with the students.
Rob also shares more stuff including how to tell if it's a boy or a girl crab.
Rob finds an enormous Stone crab (Myomenippe hardwickii)! Dr Dan warns that the crab has very strong pincers and we be careful to avoid the business end of the crab.
We are also intrigued by this strange animal. We're not sure if it's a sponge, or an ascidian.
Dr Dan is particularly concerned with the general health and biodiversity of Chek Jawa. We noticed the Haddon's carpet anemones (Stichodactyla haddoni) are looking alright. Not bleached or yellowish. And there were many of them, though not as many as before the mass deaths.
Dr Dan pointed out that the diversity was rather low compared to his previous visits. We saw some small Garlic bread sea cucumbers (Holothuria scabra) but not many of the buried Ball sea cucumbers (Phyllophorus sp.) or Thorny sea cucumbers (Colochirus quadrangularis). And only a few of these smooth sea cucumbers. We also couldn't find many Button snails (Umbonium vestiarum) on the north sand bar.
The Cake sand dollars (Arachnoides placenta) were also not as plentiful as usual. And we noticed that many live ones were broken on the undersides in the centre. Dr Dan suspects that shorebirds have pecked at the animals. I looked more closely and there were yellowish traces on the inside. Perhaps the sand dollars were full of eggs? And thus were worth picking at?
There were many of such sand dollars and even skeletons with the same kind of damage. This half dead one had attracted some scavenging Common whelks (Nassarius livescens). These snails, together with the Gong-gong (Strombus canarium) were the most plentiful animals we saw on the shore today. Other common creatures included Striped hermit crabs (Clibanarius sp.) and peacock anemones (Order Ceriantharia).
Andy saw a few Common sea stars (Archaster typicus), we saw lots of different kinds of tube worms and the seagrasses were doing well. But yeah, Dr Dan is right, Chek Jawa is not the shore it used to be before the 2007 mass deaths.

Dr Dan spent much time sharing his thoughts and ideas with Pei Rong, whom we hope will touch on Chek Jawa for her UROPS project.
We did, however, have some interesting encounters. On the northern most point, there were Terns resting near the water. Airani took lovely photos of these beautiful seabirds, but my little camera couldn't make it.
On the way home, some of the students found a Slender sea moth (Pegasus volitans). Here's Andy filming the tiny fish with broad wing-like pectoral fins. Yet another find by the students was a little Leaf porter crab (Family Dorripidae) 'carrying' a tiny sea pen. And another Sea moth too, a much tinier one this time.
And just before we got back to the high shore, a humungous Mud crab (Scylla sp.) is spotted! Dr Dan and Rob shows how to safely handle this massive crab, and Siva shared some interesting information about it.
We had a quick stop at House No. 1 for a refreshing drink from the vending machine and a scenic view of Pulau Sekudu. A great spot for a group photo at the picturesque old house.
Dr Dan points out this mislabelled photo in the exhibits at House No. 1! Wow, I must have walked past this sign a zillion times and failed to notice this error. This, of course, is a Thorny sea urchin (Prionocidaris sp.) and not a sea star!
We end the trip with a lovely dinner, starting with the Lunar New Year specialty! The very sporting waitresses explained the symbolism of the various ingredients that went into the festive dish.
Then of course everyone tossed with gusto!
What a wonderful day out with great company! I learn so much as usual from Dr Dan.

Other things I learnt today: the traffic situation at the bumboats was vastly improved this Lunar New Year. The queue was very well managed with orderly and quick departures even at the 'peak hour' of sunset. Unlike the horrendous experience Chay Hoon and I had last year.

And Airani pointed out that there is NO LONGER any free parking at the URA carpark near the Changi Jetty! Indeed, the signage shows this.
There were large crowds on Pulau Ubin and on Chek Jawa today. From the Jejawi Tower, I saw a tent set up among the trees near the boardwalk!
And when we got there, the large group of people at the tent were just packing up to go home.
On the one hand, it's nice to see ordinary people enjoying Chek Jawa. But the massive numbers was rather unnerving.

More about this trip
Airani's photos on Siva's flickr and the Duke University students' blog about their trip.

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