Semakau Landfill on a Sunny Day

Well, anything is better than a rainy day, even though I have admit it really got burning hot towards the end of our walk.

Anyway, I was out on Semakau Landfill with a group of enthusiastic visitors again today! And our group name is Spider Conch!


The sun rise was simply stunning when we were on the boat! And YES! We got to depart from Marina South Pier today since we had more participants and could get a bigger boat.


We soon reach Semakau Landfill, and unfortunately, we still have to walk from the jetty to the intertidal area again today. Luckily, it still wasn't very hot then :P


As usual, my visitors asked me what are the brown and bluish stuff near the seagrass meadow, and were rather surprised to hear that they were sponges (Phylum Porifera)! Well, guess this group comprised mostly adults who didn't watch SpongeBob SquarePants. Sponges are simple marine animals that feed on tiny organic particles and plankton in the water.


As usual, I took a group shot of the gang crossing the "river" of seagrasses.


Like yesterday, we found lots of common sea stars (Archaster typicus) in the pseudo-mating position. The one on top was the male, while the one below was the female. When the tide came in, they would release sperm and eggs into the water for external fertilisation.


In the distance, we could see lots of grey heron (Ardea cinerea), probably hunting for little marine animals stranded in the tidal pools during low tide.


We didn't managed to find a seahorse today, but fortunately we found its relative, a pipefish (Syngnathidae) instead.


The noble volute (Cymbiola nobilis) is a pretty sea snail which feed on other snails and clams.


We had been seeing their capsules, and sometimes the adult snails as well, but this was the first time I saw a spiral melongena (Pugilina cochlidium) in the process of laying eggs at Semakau Landfill!


These sea slugs are called nudibranchs (Chromodoris lineolata). "Nudibranch" means "naked gills", referring to the flower-like gills on the back of the slug.


This feathery thing is actually a worm that lives in a tube! Called fanworm (probably Sabellastarte indica), this animal uses the feather-like structures to collect any edible particles in the water.


Many of my visitors were really excited to see this beautiful ocellated sea cucumber (Stichopus ocellatus). This is a rather common sea cucumber on Semakau.


Another type of nudibranch we saw was the polka dot nudibranch (Jorunna funebris). This nudibranch feeds on sponges.


As tide was a little higher today, we had problem finding the knobbly sea star (Protoreaster nodosus) initially. I had to wade out quite a bit before I managed to spot one. And of course, we just had to take the traditional group shot with this pretty sea star!


Here's a closer look at the knobbly sea star.


Semakau is also a great place to see huge colonies of hard corals. The above is a boulder coral (Family Favidae). These corals are colonial animals, and every hole you see in the brown structure above contains one coral animal (called a polyp)!


Yet another type of nudibranch we saw was the Gymnodoris rubropapulosa. This sea slug actually feed on other sea slugs, including other nudibranchs of the same species!


Found this scallop (Chlamys sp.) in a tidal pool. Scallops can swim by opening and closing their shells, just like the way you see in Chinese opera (if you are from my generation or older, that is, then you may have seen this before).


This is the species of sea cucumber that is usually eaten during important occasions by the Chinese. It's called sandfish (Holothuria scabra) because they are usually found on a sandy substrate and they can burrow into the sand.


Found this sand collar, which is actually the egg capsules of a sea snail called the moon snail.


And near the sand collar, I saw a trail on the sand, digging into the sand at the end of the trail revealed a pretty moon snail with a very smooth shell. This snail eats other smaller snails! It has a foot which can get bloated up with water, and it will wrap its foot around its prey to try to suffocate it. It can also secrete an acidic liquid to soften the shell of its prey, and use its radula (something like a tongue) to slowly create a hole on on the shell of its prey, so that it can feed on the latter while they are still in their shells!


Soon, its time to go, and on the way back, we stopped by the huge mangrove tree to take a look at the fiddler crabs. The above is a porcelain fiddler crab (Uca annulipes). Only the male crabs have one enlarged claw, and they use them to attract the female crabs! They can only feed with their smaller claws though, as the enlarged claws are often too big to be used for feeding. Fiddler crabs feed on detritus, which are basically tiny bits of organic particles.

And after the fiddler crabs, it's time to head back for the landfill tour followed by a quick video presentation showing how the landfill operates, before we took our boat ride back to main land.

While the day was rather hot sunny, I must say that it was a really wonderful walk. Special thanks to my visitors for being such a wonderful audience despite the long walking distance and the scorching sun! :)