Monday, August 20, 2007

Monitoring Carpet Anemones

Carpet anemones (Stichodactyla haddoni) were one of the most hit fauna in Chek Jawa during the mass death. Before the mortality event this January, CJ guides have to keep reminding the visitors to avoid the landmine full of carpet anemones on the sandbar. Now, there is almost none found on the stretch of sandbar in Chek Jawa.

Does that mean the Chek Jawa is dead???

Nope. Chek Jawa is recovering. What was surprising is that at the south west end of the wetland, next to the coral rubble, there are many and many of unimpacted adults doing very well, near to the seagrasses. And at the end of the seagrass lagoon and the sandbars, we can also see some new and adult carpet anemones, though they are much fewer there. What is exciting is that many baby haddons are coming back at the extreme edge of the north of Chek Jawa. They come in very small to bigger sizes.

The plan to monitor these guys is to mark and follow the growth of 25 individuals from the impacted area and then 5 older and healthier anemones from the south west end. The idea is to measure diameter of the disc and then count tentcles in 1 cm square areas to plot it over time as we continue to monitor in the future.

I was privileged to have Ria as the photographer of these 30 anemones marked for monitoring. Her camera takes really good and sharp photos and it makes counting of tentacles easier. She has also done a great job in labelling the photos, so I can concentrate more on counting the tentacles. After cropping each photo to focus on the 1 cm squares, it is about time to start counting 30 x 2 = 60 squares of tentacles.

How did I count them? Use MS paint to dot each tentacle after counting it so I won't lose count. And after a few, lethargy sets it, it is NOT easy!

Especially when there are more than 100 tentacles in the square. Thank God that Liana helped out a bit too, making the work more bearable. She wasn't as complaining as me though...Haha.

After more than half a day of effort, finally DoNE! :-)

(All photos taken by Ria Tan)

Thursday, August 16, 2007

Chek Jawa Monitoring trip

Dr Dan was in town more than a week ago when he also visited Chek Jawa. After some discussions, we decided to focus on some prominent and charismatic fauna to monitor recovery from the mass death in January.

This time round, I'm heartened to see many friends volunteered despite it being on a weekday morning. Because the meeting time was kind of too early for most of us, some overnight-ed in school. Gave a briefing shortly to Ron and Gywnne who arrived first which was good because there were much to explain and its good to have people knowing what we are doing.

I'm apologetic to Ron and Shuying especially for helping me rush some logistic tasks till 1am before we take a short sleep (sorry also you all slept so little). Woke up at 4am this morning, and not too soon, got a phone call from Robert that he is approaching in 5-10 minutes. Hahaha. Quickly and sleepily, we grabbed our stuffs and pooled taxi to Changi Point Ferry Terminal. My taxi driver drove like a madman and we arrived much earlier. Upon arrival, I was searching my bag upside down for my wallet and good grief, there was no sight of it and I thought most likely it's in school. Thanks to Huijia and Shuying who paid first for me. When we proceeded to the basement waiting for others to come, I took out some food for those who wants breakfast and the wallet was in the food!

Everyone was punctual for the trip and we left at 5.15am after YC ran to get coffee (he was kind of running from "ladies" of Changi V). Here's a group photo on Mr Chua's bumboat as we leave mainland Singapore. For a couple of them, it's their first time to Ubin and Chek Jawa.

When we were there after a van ride from Mr. Chu, it was total darkness with a clear night sky of stars. Orion constellation was well position along the way we were walking towards the shore. After some briefing and organisings, each group of people were despatched to do their allocated stations. We spent close to one hour in the dark before day break with a tinge of light. (Photo by Paul)

This is Huijia's task of finding these button shells and placing them on a tray with grid to determine their sizes and location subsequently with GPS. To our dismay, one GPS was down and I had to run all over CJ to give points, it was a great exercise though. Huijia did a great job finding these button shells though they were not obvious to find.

I passed my camera to her later to take more button shell photos. Everyone were working hard to complete their given tasks. The priority is definitely the carpet anemone team where we have Ria explaining in detail at wildfilms blog how the process goes about monitoring them.

We also have the other great groups doing peacock anemones, cyanobacteria mussel beds, sandstars and sand dollars.

There were a few featherstars (Class Crinoidea) spotted along the way and we were excited to spot the first one.

And here's more found by Dickson and Robert. Didn't see them in CJ before and they don't live on sandy areas, but on reefs. They don't look like CJ residents and definitely were washed off from a nearby reef where it might be impacted.

As I was browsing through Paul's photos, was pleasantly glad that seahorses still can be found in Chek Jawa. More creatures found by the intrepid team are the geographical and hairy sea hares, luidia eight-armed star, brittlestars, baby sandfish sea cucumbers etc etc.

We finished our job on time as the tide returned and finally everyone can take a nice slow pace to enjoy the serenity of Chek Jawa. I really like these Delek flowers that smell bit spicy yet like Tembusu flowers.

Here's a group photo (taken by Ria) where we posed at the end of the monitoring. Believe everyone had fun at the same time as we marvel at how CJ is recovering. Returning to the visitor centre, our hungry stomaches were treated to breakfast kindly prepared by Ria. Thanks.

Thank you Ria, Ron, Robert, Gwynne, Huijia, Yuchen, Yuan Ting, Pei Hao, Paul, Dickson, Yijun and Shuying for taking time out and all the wonderful help. Whatever data we have got today will be very important for us to better understand the vulnerabilities of our living shores and better appreciate their nature and response to danger.

Thanks also to Siva, my supervisor and also Choon Beng from Nparks Ubin.

Thank God no rain until immediately after we boarded the returning van! The heavy downpour was terribly heavy.

Wednesday, August 8, 2007

Chek Jawa Festival!

Last Sunday was a festival for Chek Jawa! Not only the CJ project gang was there, Naked Hermit Crabs, Green Volunteers Network and the NIE green club were there too. Literally, it is the first time seeing Chek Jawa so lively and crowded (simply because I've not been there on a Sunday before).

Dr Dan is in town and we can't wait to visit Chek Jawa together on a cooling Sunday morning. Other than Siva and company, Dr Dan also brought along his wife too and everyone was very excited. (Photo by Ria)

Though the tide wasn't spectacular, it was good enough for us to learn so much from this trip. Dr Dan is an expert of the shores and we take this golden opportunity to learn from him.

From this photo you can see the exposed part that it is actually the opportunistic colonization of these mussel beds. It is seen as a thick 'carpet' of tiny mussels that trap a soft bed of silt by creating a communal nest of byssus threads. These mussels are probably Musculista sp. which incorporate sediments, bits of broken shells and other debris into the mussel nest. The nest is pockmarked with little slits, each housing one mussel.

Dr Dan was very excited to know that these were not seen in Chek Jawa before and he speculates that the common seastars might eat them. Siti once shared that their presence is due to freshwater influx, which I kind of doubt. Are they cyanobacteria too?? Have to really learn more about them yeah. (Photo by Ria)

What eats these mussel beds? We have to find out how transitional are these patches and will the recovery of common sea stars cause the future disappearance of these mounds? Watch out for it.

We headed towards the northern sandbar towards where the button shells are. If you slightly remove the top surface of the fine sand, you will be amazed to see these jewels of Chek Jawa! These snails are actually preyed upon by moon snails.

Dr Dan was excited, as heard from this video, that these button shells are back (or they might all along be there). Take a look at this video as Ria, Siva and Dr Dan shares the interesting facts of these button shells and how they disperse when disturbed.

I did not take many photos because was busy at work. For more information of the trip, please take a look at wildfilm's account by Ria.

We were looking out for the top 5 charismatic macrofauna to monitor. They are..drum rolls..

1. Carpet Anemone (Stichodactyla haddoni)
2. Peacock Anemone (Order Ceriantharia)
3. Button Shells (Umbonium vestiarum)
4. Mounds of mussel beds (probably Musculista sp.)
5. Cake Sand Dollar (Arachnoides placenta)
6. Common Seastar (Archaster typicus)- Watching out for their comeback!

For the next field trip, we will be monitoring a maximum of 25 Haddon's carpet anemones and to study their growth (through tentacle density) and locomotion over time.

Towards the end of the shore trip, Ria found this interesting polychaete.

We proceeded for a quick boardwalk with Dr Dan and chanced upon these overly-enthusiastic visitors climbing down to the sandbar though they are not allowed to. And it is also a dangerous act for both the visitor and the animals. For the visitor because the tide can come in faster than you can imagine and you will be trapped.

Dangerous for the animal because as curious beings, we may tend to disturb the precious lifeforms of CJ. Look at how they use a stick and poke at most probably a carpet aneomne. Seriously I hope they can leave the anemone guys alone and allow them to recover.

It was an interesting first half of the morning. As we bidded farewell to Dr Dan and gang, Ria and I headed towards the mangrove boardwalk to join for the recce of Naked Hermit crabs.

Wow, another banded krait was spotted!! These snakes are very venomous, far worse than cobra.

Further towards the house no. 1 side on the coastal boardwalk, Ria introduced this portion where a landslide had occured before. Good for geography lessons.

The pong pong trees along the streets were once imported but this one here is native.

I always like to find the seashore nutmeg tree that is already rare in Singapore.

Towards the end of a 5 hour field trip, the finale was this spider with a net of orange mass.

If you look closer, they are babies!!

This hut outside CJ is so lively and it is really a wonderful end of the series of low tides last week. It's heartening to see many people coming to appreciate the beauty of nature.

Thanks Ria for the wonderful lunch you treated to the NHC people and also the urgent ride to my tuition afterward.

Thanks Siva, Dr Dan and company for coming and sharing much with us.

Saturday, August 4, 2007

Recovery on the way... Let's not spoil it

Just moments after the sunrise, I was accompanied by Yikang on a Friday morning to do some monitoring for my project. I'm glad that Ria and Marcus also came along. We also met Swee Cheng and Chee Kong along the way who are doing their own research work.

All seems ok and fine at first, but soon I found out that there are some litter along the sandbar shores. I didn't think too much at first and proceeded straight to the extreme north myself while Yikang helped me to take photos from the observation tower to monitor sandbar and cover changes over long periods of time.

This extreme part is remote and it was my first time going there. It looks ugly with the fence to deter illegal immigrants from swimming across from Johor. It is a narrow stretch of beach that goes on and on. Without the liberty of time, I had to start work.

There are many large oyster and shells around this part of the shore. Is this one being pried open for harvesting?

My first job is to actually take GPS readings along the edge of the sandbar so that I can get an outline of the current sandbar position.

While walking south from the extreme north part, I was pleasantly surprised to see many many of these tiny Stichodactyla tapetum, Stichodactyla haddoni and the Swimming anemones (Family Boloceroididae). The north part used to be almost completely barren of anemones.

A really good sign of recovery!

Walking a bit more south, I ignored most of the cyanobacteria patch as they are really too common. But this particular patch looks more interesting. Something struck my eye.

What are these pink and yellow things spreaded out in large numbers?

These bunches of pink and yellow stuff that looks like a carnation are actually eggs of a muricid snail! Why does the cyanobacteria favour these snails?

The echinoderms are making a good come-back to CJ including this sea cucumber.

And these baby sandfish sea cucumber too! Can't forget the sight of the mass death where many of these adult ones were found dead in huge numbers. Welcome back.

Along the apparently-lifeless sandbar, some markings were found.

Found a huge family of brittlestars burrowed into the sand! First time saw this. Hopefully, soon followed will be the common seastars.

Not only for brittlestars and sea cucumbers, we also found many sandstars that are very small. These babies are really cute and I hope they will grow up and live well in Chek Jawa.

These Halophila beccarii seagrasses can now be found near to the boardwalk instead of the extreme north end, and it is suggested that the fresher waters caused it.

What I couldn't stand is the enormous amount of litter found on the shores. We at first thought it might be drifted from elsewhere like Johor.

What confirms us the source of litter is this bowl of instant noodles with the remains noodles and soup in it! How can such a thing be from elsewhere? The content inside is still intact.

It must most probably be from the boardwalk, since it has been recently opened.

If it's true, what a shame.

After the terrible incident of stepping on a sharp object the other time, one has to be extremely careful because there are planks with rusty nails pointing upwards. Watch where you walk!

The busy day ended with a shot of the rear beacon which I have never took effort to notice it.