25 October 2012

Dredging, more talks and isopods at the Northern Expedition Day 10

Yesterday, I joined the dredging team that have been working every day throughout the Expedition. There are limited places on the boat so I didn't get to go until now. Here is Dr Bertrand setting up a net for a dredge, next to him, the yellow sled dredge and the brown beam dredge.
Many interesting creatures were found, we had another series of exciting talks in the evening and enjoyed a great dinner too.

Dr Bertrand leads the dredge surveys. His vast experience in doing deep dredges and other exotic submarine explorations really helps the Expedition get great samples. He told me later that he has done 20 dredges in a day! Dr Bertrand and Swee Cheng handle the dredge which is released at the back of our boat the Galaxea, while Chee Kong manages the winch that lowers and brings up the dredge as well as the A-frame that controls the location of the dredge. In this photo, a beam dredge is being used with which we survey larger animals such as crustaceans and fishes.
Another kind of dredge used is the yellow Epibenthic Sledge, which collects fine sediments that accumulates at the end of the funnel like thing riding on the yellow sled. This is great for finding tiny creatures such as nematodes, isopods and more.
Besides the big winch on the boat, for a quick dredge, the team uses a more manual method of deploying the net on a long rope with the length marked up. It takes teamwork to manually pull up the net, with Dr Fujita helping to coil up the rope as it comes in.
We dredge several times in three locations around Pulau Tekong.
The amount at each dredge is small, filling only one tray. We quickly pick out all the delicate animals, pack them away in container and put them on ice.
For a dredge with tiny animals, we take a little more time to get as many as we can.
Sometimes the sediments are fine. Other times we get a lot of broken shells.
Some of the stunning creatures we found include crabs with super long legs, lots of large sea urchins and many colourful Sea apple sea cucumbers.
Among the exciting animals I saw was this little crab carrying a sea anemone. The sea anemone creates a flat platform made of chitin (the same substance that insect exoskeletons are made of). The crab then carries the platform. It was Prof Daphne who first told me about this, and she heard of this crab from Prof Peter.
Another interesting animal was this little Pebble crab that seems to be covering its eyes with its pincers.
Along the way, we spot a flock of terns. A separate team have been surveying Singapore's sea birds about every month or so, and have spotted all kinds of sea birds as well as dolphins! More on Con Foley's blog with awesome photos.
Dr Fujita and Cheng Ann pose for a shot during a quiet moment in the trip.
The first thing we do when we get back from the dredge is to log in our finds with Joo Yong who is managing the database for the Expedition. We get our sample numbers which will allow all the specimens to be tracked throughout the many steps that will be done to make sure they are sorted, photographed, tissues sampled and properly preserved.
When we got home, we see Dr Daisuke with a big tray of pufferfishes.
The pufflefishes were apparently full of huge parasitic isopods. It takes lots of people to take good photos of these parasites.
Photo by Rene Ong on facebook.
The volunteers have been hard at work sorting while I was out with the dredging team.
After a quick late lunch, I get around to sorting the dredged stuff and find lots that we couldn't do properly on the boat. Tiny balls of sponges, tiny shrimps and crabs, lots of clams and more.
In the late afternoon Dr Tan Koh Siang, the Expedition Leader brought around some Outward Bound Singapore staff to have a look at what we are doing. Dr Ng Heok Hee is checking out what animals can be found in dead wood and we are delighted to show them some snapping shrimps and crabs that he has carefully extracted.
Dr Bertrand and Yoyo show the OBS staff the sea urchins we dredged up in the morning.
Someone exclaimed that the sea urchins look like aliens. While indeed they do look strange, these creatures are all Singaporeans too!
Later in the evening, it was time for more short talks by the scientists of the Expedition. Dr Sumaitt gave a wonderful talk about sponges of Thailand. With lots of beautiful photos of sponges, Thailand's amazing shores and the work being done for marine conservation there. I've been waiting for his talk since I glimpsed his photos on his laptop.
He explains how we need to look at tiny internal structures to be able to identify the sponge. This is why we need to collect samples. It is difficult to identify sponges for sure simply from a photo.
Dr Sumaitt does database work with his cat! So sweet.
Dr Neil shared about parasitic isopods on fish. While the thought may seem icky, I found the isopods quite fascinating as he shared beautiful photos of them.
Once again, tiny parts of the tiny animals must be studied to identify them.
Dr Li also shared the work done in China for marine biodiversity. With such vast marine resources,  impressive work has been done for them.
My favourite talk was by Dr Kevin who shared about bryozoans. These super tiny animals come in colonies that may have beautiful flower-like forms. His photos do help us keep a look out for them as we sort the stuff that comes in every day.
To identify bryozoans, we need to use a super strong microscope to see the structures including the beautiful 'boxes' that they build to live in. Dr Kevin also shared a video clip of the polyps living in the soft transparent colonies that the volunteers have dubbed 'tang hoon' because they do look like transparent noodles.
This evening, we gather once again at Ubin Town for another nice dinner.
Our sponsor Asia-Pacific Breweries have kindly provided lots of much-needed free beer tonight. Dr Daisuke wants all the beer to himself! Just a joke of course, there was more than enough for everyone, even Dr Daisuke couldn't drink it all up.
Dr Daphne and I are intrigued by the clams that have been served to us. Are they the same species? No worries, Dr Tan Koh Siang to the rescue, they are all Marcia marmorata, a kind of Venus clam that is notoriously variable. I saw lots of them during the Pulau Sekudu survey. Whatever their shape, they were delicious.
There have been lots of media articles about the Expedition after the VIP and press visit the day before. These include Chinese media reports, all consolidated on the Raffles Museum News blog. The Expedition has even been reported in The Star of Malaysia. All news articles are also updated on wildsingapore news.
The Raffles Museum News blog also shared a sneak peek at some of the gorgeous photos taken by the professionals at the Photo Station of the Expedition.
Also just in, great snapshots of the happenings so far by Thanh Son Nguyen on facebook. Capturing the many people hard at work during the Expedition.
Photos by Thanh Son Nguyen on facebook
Today is a designated and much needed rest day for all of us. Tomorrow, it begins again with a vengeance as the low spring tides start again. The frenzy of field trips will begin again, as dredge surveys continue. Lots of work for everyone at the sorting, photo, tissue and other stations.

No comments:

Post a Comment

LinkWithin

Related Posts with Thumbnails