Semakau over 2 days

I was back at my favourite island, Pulau Semakau, again 2 days in a row. On Friday, it was to help with some Okto TV programme, while on Saturday, I was the coordinator and hunter-seeker.

Friday's trip did not really went on that smoothly, as the TV crew arrived late, and we had to rush through the shooting due to the rising tide and did not managed to see much. Saturday was great though, since the tide was excellent, and I managed to find quite a number of interesting stuff :)


My top find of the trip must be this huge Cushion Star (Culcita novaeguineae). It's been almost a year since I last saw this particular individual! And frankly, it seemed to have grown even bigger than before, about 30cm wide and quite heavy. It felt like meeting an old friend :)


It took me quite a while to find our resident Tigertail Seahorse (Hippocampus comes). It was a distance away from her usual spot, probably due to the super-low tide. I couldn't find the male though. Guess there were just too much algae around. And how do I know it's a female? It has an ovipositor (fin-like structure below its belly) which it uses to deposit her eggs into the male's pouch. Male seahorses have a brood pouch to hold the eggs before the little seahorses are hatched.


I had to walk quite a distance before I found my first Knobbly Sea Star (Protorester nodosus). And somehow after I found it, the others just started appearing like magic. One of the knobblies had 3 shorter arms - appears that they were chomped off, probably by some predator. The arms are in the process of regeneration though.


I also found this Sandfish Sea Cucumber (Holothuria scabra). This sea cucumber is the one normally found in Chinese restaurant, served as a delicacy. They must be properly processed before they can be consumed though to remove the toxins.


It was quite a day for nudibranchs! Several were spotted including this Black Margined Glossodoris Nudibranch (Glossodoris atromarginata) which I found on a seaweed.


Several Chromodoris lineolata nudibranchs were also spotted. I did not show this particular one to the visitors since the other hunter-seekers had found a few already. The term "nudibranch" means "naked gills", refering to the flower-like gills found on the back of many species.


Nudibranchs are sea slugs - basically snails without shells. And the reason they have adapted such that they do not need a shell for protection is that they have developed other defense mechanism. This Black Phyllid Nudibranch (Phyllidiella nigra) is said to be able to secrete toxins to its surrounding when it is stressed. The toxins are so strong that the whole fish tank of fishes can be killed! Helen found one of this nudibranch, while I found another.


This is a Pustulose Phyllid Nudibranch (Phyllidiella pustulosa), another nudibranch with toxins. Found many of them during the trip, though the one above was found by LK.


The tide was so low that even our resident Fluted Giant Clam (Tridacna squamosa) was exposed. This is probably the biggest clam species in Singapore, and is able to grow to about 40cm wide.


I found this Hell's Fire Sea Anemone (Actinodendron sp.) while searching for the knobblies, but unfortunately it was a distance from the main route and being a sessile animal, I couldn't use it for the guided walk. This sea anemone can give very painful stings.


This little Dragonfish Sea Cucumber (Stichopus horrens) was also found away from the main route, and since LK has already found one, we didn't show it to the visitors too. This sea cucumber has an unusual way to protect itself from predation - by detaching a piece of its skin to distract predators when attacked.


This Noble Volute (Cymbiola nobilis) was spotted in the seagrass meadow where we usually make the crossing, but only after the visitors had gone back to the washup point. This snail is a predator of clams and other smaller snails. To feed, it wraps its huge foot around its prey in an attempt to suffocate it. When the prey eventually opens up to breathe, the volute will feed on it.


Other hunter-seekers found this Heart Cockle (Corculum cardissa), but it didn't look like it's in a good shape though.


ST found this Spider Conch (Lambis lambis) near where I found the Sandfish Sea Cucumber. This edible snail is over-collected in some places.


Near the reef edge, Helen found this huge Ocellated Sea Cucumber (Stichopus ocellatus). It has lots of 'eyespots' on top, which are believed to have some sensory functions or help the sea cucumber move around and hold to surrounding hard surfaces.

Apart from the above organisms, I also found a pygmy squid, synaptid sea cucumber, while the others also found an upside-down jellyfish, juvenile fluted giant clams and many other interesting stuff.

This was certainly one of my favourite trips so far this year!