Saturday, June 19, 2010

Exploring Sekudu on 16 Jun 2010

This is a slightly overdue entry again. We made a trip to Pulau Sekudu last Wednesday to check on the situation there after the oil spill. Pulau Sekudu is part of Chek Jawa Wetlands, and hence is a protected area. As such, we had to get a permit from NParks before we can go there.

When we reached the island, we were glad to see that the oil spill did not appear to have affected it. We did not see any huge patches of crude oil. It started raining soon after we reached the island though, and hence we can't exactly tell if there were any oil stains on the wet rocks.

We did not managed to explore the island properly due to the rain, and in fact, many animals were probably hiding from the down pour. But still, we managed to see a number of marine organisms before the rain eventually got too heavy and lightning started flashing.

Cake Sea Star (Anthenea aspera
We found several orange-coloured Cake Sea Stars (Anthenea aspera). Most of them were less than 10cm wide though. Not sure where did the bigger ones go.

Biscuit Sea Star (Goniodiscaster  scaber)
There were many Biscuit Sea Stars (Goniodiscaster scaber) of various sizes. However, they appeared to be less abundant compared to last year.

Luidia  maculata
Forgot to wipe away the water droplets on my lens, and hence this Eight-armed Luidia Sea Stars (Luidia maculata) appeared slightly distorted. This sea star feed on other smaller sea stars!

Knobbly Sea Star (Protoreaster nodosus)
We found 2 rather huge Knobbly Sea Stars (Protoreaster nodosus)! It got its name from the nodules on its top side.

Feather Star (Class Crinoidea)
We found 2 Feather Stars (Class Crinoidea) too! These animals gather small food particles in the water using their feather-like arms.

Pencil Sea Urchin (Prionocidaris sp.)
There was a Pencil Sea Urchin (Prionocidaris sp.) at the coral rubble area. The water got too murky further out, and hence we did not venture further to try to find more of them.

Salmacis Sea Urchin
The Salmacis Sea Urchin (Salmacis sp.) appeared to be in season, and we saw many of them. Most of them had bits and pieces of shells, twigs or seaweed stuck to them for camouflaging.

Ball Sea Cucumber (Phyllophorus sp.)
There were several Ball Sea Cucumbers (Phyllophorus sp.), though certainly not as abundant as last time.

Paracaudina australis
A few translucent sea cucumbers were found, probably Paracaudina australis.

Sea Pen (Order Pennatulacea)
Among the seagrass, I found quite a number of Sea Pens (Order Pennatulacea).

Stinging Hydroids (Class Hydrozoa)
There were clusters of Stinging Hydroids (Class Hydrozoa) too! These plant-like colonial animals can give nasty stings when touched.

Haddon's Carpet Anemone (Stichodactyla haddoni)
There were many huge Haddon's Carpet Anemones (Stichodactyla haddoni) among the seagrass, and quite a number of them were at least 40cm wide. These anemones have sticky tentacles to sting and stick small prey like fishes or crustaceans.

Swimming Anemone (Boloceroides mcmurrichi)
Swimming Anemones (Boloceroides mcmurrichii) appeared to be in season too. These sea anemones do not attached themselves to the substrate, but are free-living! They can swim by pulsation.

Soft corals
It was nice seeing so many brightly-coloured soft corals.

I found a transparent shrimp living on one of them. Looks very much like some kind of snapping shrimp, but can't say for sure.

Ghost shrimp
There was a ghost shrimp out of its burrow. Not sure about the species though.

Blue Dragons (Pteraeolidia ianthina)
Some of the volunteers found 2 Blue Dragons (Pteraeolidia ianthina) together. Wonder what they were doing?

Blue Dragon (Pteraeolidia ianthina)
Here's the bigger one when they moved apart. This nudibranch feeds on hydroids, and is able to store the latter's symbiotic algae in its body for photosynthesis. The algae will provide nutrients for the nudibranch. At the same time, it can store the stinging cells of the hydroid and use them for protection against predators as well.

Denison's Nudibranch (Dendrodoris denisoni)
Another nudibranch we saw was this Denison's Nudibranch (Dendrodoris denisoni). Unlike the Blue Dragon, this nudibranch feeds on sponges by secreting enzymes to digest them externally before sucking them up.

Natica zonalis
We saw a few moon snails, including this Natica zonalis.

We also saw a few octopuses. They are among the smartest invertebrates around, and are known to be able to learn by trial and error.

Razor clam
We also saw a few razor clams. This one was next to an anemone.

After exploring for about an hour plus, the rain got even heavier, and soon, we could see lightning too. For safety reasons, we decided to take shelter near the big rocks at the centre of the island.

Due to the storm, we did not managed to explore most part of the island, and many of the organisms were probably hiding. However, we were still very glad that we had made this trip, as we could now be sure that Sekudu was indeed spared from the oil spill.

Thursday, June 17, 2010

Semakau Walk on 17 Jun 2010

Have been really busy again, and hence did not have the time to blog about quite a number of things that I have done recently. We did a guided walk today at Semakau, and here are some quick highlights of the things we saw.

Nautilus shell (Nautilus sp.)
My most exiting sighting today would be this Nautilus shell (Nautilus sp.) that was also spotted by Casey last weekend! Related to octopuses, squids, cuttlefish, nautiluses are the only cephalopods with a hard external shell. They usually live at depths of several hundred metres, but usually rise to shallower waters to feed at night. Empty shells, like the one above, are sometimes washed up on beaches. This shell appeared to be in rather good condition, which could mean that the animal might have died recently!

Tomato Clownfish (Amphiprion frenatus)
Another nice sighting for me would be this Tomato Clownfish (Amphiprion frenatus). While I had seen this animal several times already, this was the first time I encounter such a friendly one and managed to get a shot of the entire fish! Unfortunately, the Bulb Tentacle Sea Anemone (Entamacea quadricolor) appeared to be rather bleached. Many of our corals and other cnidarians appeared to be bleaching recently, a rather worrying sign. Hopefully they will recover soon.

Knobbly Sea Stars (Protoreaster nodosus)
I also chanced upon the population of Knobbly Sea Stars (Protoreaster nodosus). I didn't stop to properly count how many were there, but in this photo alone there were more than 10 of them. Would say there were probably close to or more than a hundred of them around this area!

Knobbly Sea Star (Protoreaster nodosus)
Here's a closer look at one of the Knobbly Sea Stars.

Cushion Star (Culcita novaeguineae)
We also saw this mature Cushion Star (Culcita novaeguineae), which was about 20cm across.

Cushion Star (Culcita novaeguineae)
And once again, we spotted this juvenile cushion star, which was only about 10cm wide. We first saw this particular individual in May last year, when it's much smaller, flatter and was greenish in colour. The colour slowly changed to yellowish, and now it's getting more bloated, looking more and more like a cushion!

I saw this clam which has lots of spines on it, but not sure what species it is.

Fluted Giant Clam (Tridacna squamosa)
As usual, we saw the resident Fluted Giant Clam (Tridacna squamosa).

Heart Cockle (Corculum cardissa)
I chanced upon this pretty Heart Cockle (Corculum cardissa). Unfortunately, due to its nice shape, it was often collected to be sold at souvenir shops in the region.

Ovum Cowrie (Cypraea ovum)
The Ovum Cowrie (Cypraea ovum) has a nice and smooth shell, which it protects with its mantle. The bumpy mantle also helps to camouflage the animals.

Noble Volute (Cymbiola nobilis)
I saw 2 Noble Volutes (Cymbiola nobilis) today. These snails feeds on other shelled mollusc by wrapping their strong feet over the prey to suffocate them.

Moon Snail (Polinices mammilla)
Here's another fierce predator of snails and clams - the Moon Snail (Polinices mammilla). It can secrete an acid to soften the shell of its prey before drilling a hole through it to feed on the meat inside, with a tongue-like structure called a radula.

I saw this cute little octopus stranded in a small pool of water while heading back to check on the groups.

Bohol's Nudibranch (Discodoris boholiensis)
This Bohol's Nudibranch (Discodoris boholiensis) is often mistaken to be a flatworm, as it's really flat!

Funeral Nudibranch (Jorunna funebris)
The name "nudibranch" means "naked gills", referring to the the flower-like gills on the back of most species, such as this Funeral Nudibranch (Jorunna funebris).

Dragonfish Sea Cucumber (Stichopus horrens)
Not sure why, but there were many Dragonfish Sea Cucumbers (Stichopus horrens) today. I probably saw like almost 10 of them.

Sandfish Sea Cucumber (Holothuria  scabra)
We only found 1 Sandfish Sea Cucumber (Holothuria scabra) though. This is the species that is found in Chinese restaurants. Note that they must be probably processed to remove the toxins in them before they can be eaten though.

Stonefish Sea Cucumber (Actinopyga lecanora)
The Stonefish Sea Cucumber (Actinopyga lecanora) got its name from the fact that it's commonly found sandwiched between rocks, appearing just like a stone!

Spotted-tail Frogfish (Lophiocharon trisignatus)
And here's one master of camouflage that's really hard to spot. It's a Spotted-tail Frogfish (Lophiocharon trisignatus).

Tigertail Seahorse (Hippocampus comes)
This female Tigertail Seahorse (Hippocampus comes) appeared a little fatter than usual. Wonder if it had eggs in its belly, ready to be transferred to the male?

Adhesive Sea Anemone (Cryptodendrum adhaesivum)
I spotted several Adhesive Sea Anemone (Cryptodendrum adhaesivum), which appeared to be rather bleached too.

There were a lot more other things that we saw, as today was an exceptionally good day. In fact, our walk today over-run quite a bit because of that. Hopefully all the participants had enjoyed themselves! :)

Monday, June 14, 2010

Project Semakau Volunteer Recruitment

Project Semakau is recruiting volunteers again!

Project Semakau is a community involvement and conservation project, driven by volunteer-based research led by the Raffles Museum of Biodiversity Research, National University of Singapore, to collect data on the biodiversity of Pulau Semakau so as to realise and enhance the island's value as a nature education and conservation site. This project is kindly sponsored by HSBC, and was launched on 14 Nov 2008.

Since then, we have recruited and train many volunteers from HSBC, NUS, NTU, various secondary schools and members of the public to assist with surveying the biodiversity of the island and monitoring the ecological changes. More details of the project can be found at

Training will be provided to ensure that volunteers are equipped with the knowledge required to assist with the research work on the island. To find out what you can see at Semakau, check out

Who can join?
Anyone with a passion for nature conservation and is 14 years old and above may join.

What will I be required to do as a volunteer?
As a volunteer, you will be required to:
A) Attend a classroom training, a biodiversity survey field trip, and a monitoring field trip.

  1. Classroom training at NUS on 22 July 2010, 7-9pm
  2. Biodiversity survey training at Pulau Semakau on 31 July (Sat) 5am-12pm, or 11 Sep (Sat) 4-10pm
  3. Monitoring survey training at Pulau Semakau on 14 Aug (Sat) 5.30am-12.30pm, or 6 Nov (Sat) 2.30-8.30pm.
B) Attend at least 6 surveys a year. Please note that for some of our surveys, you will be required to meet very early in the morning, such as 4.30am. Transport allowance will be provided. Please ensure that you are able to commit and come for such early morning trips before you sign up as a volunteer.

How to sign up?
To sign up as a volunteer, please send to by 9 July 2010:
- Full name
- NRIC or passport number
- Gender
- Nationality
- Date of birth
- Mobile number
- Home number
- Occupation
- Email address you prefer to be contacted at
- Name and contact of next of kin (for emergency contact)