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! :)

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