Semakau Walk on 18 Feb 2011

Today, we brought a group of girls from MGS to Pulau Semakau for an intertidal walk. This was our first intertidal walk of the year, and we were really lucky that although it drizzled a little during the boat ride, the weather improved when we started the guided walk and we had a really great trip! :)


I was guiding today, and my group comprised 15 very enthusiastic MGS girls! Our group name was Flatworm. Here's a group photo taken with the highlights of every Semakau trip - the Knobbly Sea Stars (Protoreaster nodosus). If any of the girls are reading this, you can click on the above photo and download a higher resolution version.

While unfortunately we did not see any flatworms, we still managed to see quite a number of interesting stuff. As this group was really enthusiastic and had lots of questions, I did not have the time to take many photos. I am not complaining though, as it's always great to have such an interested group! Here are some of the few photos that I managed to take.


Here's a Mantis Shrimp (Harpiosquilla sp.), which got its common name from its two front claws which make it somewhat resembles a mantis with some imagination. There are two main groups of mantis shrimps found in local waters - the spearers which spear their prey, and the smashers which punch their prey. The one above is a spearer. We also saw a smasher, but unfortunately it was a little too shy and fast for me to get a photo of it.


The first sea cucumber of the day was this Synaptid Sea Cucumber. It was really long - more than 1m! This sea cucumber lashed its oral tentacles to pick up fine organic particles around it to feed on.


We also saw a very pretty green Haddon's Carpet Anemone (Stichodactyla haddoni), and it had a pair of Anemone Shrimps (Periclimenes brevicarpalis)! The shrimps had a layer of mucus around them which prevent the sea anemone from stinging them, and at the same time, gain protection from predators among the venomous stings. They scavenged for left over food among the tentacles. Meanwhile, the sea anemone did not really benefit from the shrimps. This relationship is known as commensalism.


As we were walking past a tide pool, I saw a little octopus coming out of a hole! This master of camouflage changed its colours and patterns once in a while to match its surrounding.


Nearer to the reef edge, we saw lots of hard corals. This one is actually luminous! The luminous colour pigment was said to act as a sun block to protect the corals from harmful rays.


The tide is also low enough for us to see the resident Fluted Giant Clam (Tridacna squamosa). When I first saw this clam a few years ago, it was like less than 20cm wide. Now, it appear to be more than twice that size!


I also spotted this Funeral Nudibranch (Jorunna funebris) next to a Blue Sponge (Neopetrosia sp.), which was probably what it fed on.


And as we were heading back to the secondary forest, we saw a Sandfish Sea Cucumber (Holothuria scabra). This is the sea cucumber that is normally served in local restaurants. It must be properly processed to remove toxins in its body before it can consumed though.

All soon, we had to end the walk. Quoting what some of the girls said, a 2-hour walk was certainly not enough to explore this beautiful island! In fact, I would say that even for me who has been regularly visiting Pulau Semakau for the past 5 years, I still see new things every now and then!

Tomorrow, we are going to Stonefish Bay on the island to do a Project Semakau survey. Hopefully we will not encounter any stonefish, but instead will see more interesting organisms! :)