Monday, October 19, 2009

Semakau Walk on 18 Oct 2009

We were back at Semakau for a guided walk, and once again, I was the coordinator and hunter seeker. Assisting me with hunting-seeking were Meiyi and Kim.

Bakau (Rhizophora stylosa)
The tide was still quite high when we reached the reached the shore area. Thus, we decided to explore the high shore while waiting for the tide to go down. There were several Bakau trees (Rhizophora stylosa) in the area. These trees have prop roots spreading over a wide area that help them balance on the unstable mud.

Red Berry Snail (Sphaerassiminea miniata)
There were many Red Berry Snails (Sphaerassiminea miniata) under the Bakau trees. I always find them to look really cute with their little eyes.

Olive Whelk (Nassarius olivaceus)
Meiyi found an Olive Whelk (Nassarius olivaceus). Like most other whelks, this fellow is a scavenger, and uses its long proboscis to "sniff" out dead animals.

Blue-striped Hermit Crab (Clibanarius longitarsus)
And finally, I managed to get a shot of a Blue-striped Hermit Crab (Clibanarius longitarsus) in its natural environment on Semakau! Somehow the ones at Semakau are so shy, and even though I can usually find a few of them on most trips, I never had the time to wait for them to emerge and take some proper photos.

Dragonfish Sea Cucumber (Stichopus horrens)
Soon, the tide was low enough for us to get near the seagrass meadow. The first animal I found was this Dragonfish Sea Cucumber (Stichopus horrens). This sea cucumber is sometimes collected to make Air Gamat, a tonic made from the body fluid of sea cucumbers.

Sand-sifting Sea Star (Archaster typicus)
Not sure if it's my imagination, but the population of the Sand-sifting Sea Star (Archaster typicus) appeared to be growing exponentially. They were spreading over a really wide area these days.

Hammer Oyster (Family Malleidae)
At the coral rubble area, I found a Hammer Oyster (Family Malleidae). This clam has its hinge at the top of the "T".

Juvenile Cushion Star (Culcita novaeguineae)
Also at the coral rubble area was this juvenile Cushion Star (Culcita novaeguineae). Interestingly, I found it around the same spot that I found it last month!

Sandfish Sea Cucumber (Holothuria scabra)
Kim found this really fat Sandfish Sea Cucumber (Holothuria scabra).

Wondering Cowrie (Cypraea errones)
I found this Wondering Cowrie (Cypraea errones) stranded upside-down on the sand. Not sure what had happened to it. I quickly put it in a small tidal pool and it started moving immediately.

Noble Volute (Cymbiola nobilis)
I saw at least 3 Noble Volutes (Cymbiola nobilis) laying eggs during the trip. They really blend in very well to the surrounding with all the silt on their shells!

Noble Volute (Cymbiola nobilis)
This juvenile Noble Volute still looked very clean though. Interestingly, I found it just a few metres away from the previous one. This pretty snail is very fierce hunter of other snails and clams though. It will sniff them out with its long proboscis, and then wrap its huge foot around its prey to suffocate it.

Red Maiden's Fan (Oceanapia sagittaria)
Semakau has lots of these very pretty Red Maiden's Fan (Oceanapia sagittaria), a sponge which I always find it hard to resist taking photos of.

I was really glad to find this unidentified sea star again. So far, none of the sea star experts I have asked know what species it is. Somehow I wonder if it could be a hybrid...

Knobbly Sea Star (Protoreaster nodosus)
And the star of every Semakau trip must be the Knobbly Sea Star (Protoreaster nodosus)! I had a hard time looking for this one. It appeared that many of the knobblies are moving back to the far left and right side of the intertidal area again.

Black Long-spined Sea Urchin (Diadema setosum)
Near the reef edge, I spotted this Black Long-spined Sea Urchin (Diadema setosum). It has venomous spines, which break easily upon contact.

Spider Conch (Lambis lambis)
Meiyi found this Spider Conch (Lambis lambis), which has a small colony of Porites Coral (Porites sp.) growing on it! What a way to camouflage itself!

Fluted Giant Clam (Tridacna squamosa)
At the reef edge, our resident Fluted Giant Clam (Tridacna squamosa) had a little "operation", where KS and his friend collected a little of its tissue for the latter's research.

Ocellated Sea Cucumber (Stichopus ocellatus)
Not far away from the giant clam, I found the resident Ocellated Sea Cucumber (Stichopus ocellatus). This huge sea cucumber can often be found around this area.

Found this murex near the reef edge. Forgot how to tell the difference between Chicoreus brunneus and Chicoreus torrefactus (oops...), so guess will have to check with SK again to confirm the ID. Haha...

Pseudobiceros bedfordi
Bobby, who had finished his benthic survey, found this pretty flatworm (Pseudobiceros bedfordi), which we sometimes called it the Persian Carpet Flatworm due to the beautiful patterns on its back.

Juvenile Cushion Star (Culcita novaeguineae)
Some of the benthic surveyors also found another juvenile Cushion Star.

Sunflower Mushroom Coral (Heliofungia actiniformis)
We managed to plan the route such that the groups got to pass by this lovely neon green Sunflower Mushroom Coral (Heliofungia actiniformis).

Acoel Worms (Family Acoela)
However, it was only when I got home to process the photos when I noticed these little brown patches on it. These were Acoel Worms (Family Acoela), which are believed to feed on copepods or secretions from corals or other sessile animals. Traditionally thought to belong to the phylum Platyhelminthes like other flatworms, recent molecular phylogenetic analyses suggest that they are something different altogether.

Maritigrella virgulata
Robert later found this Maritigrella virgulata flatworm, which I have only seen a few times on Semakau.

Orange-spotted Nudibranch (Gymnodoris rubropapulosa)
Several Orange-spotted Nudibranchs (Gymnodoris rubropapulosa) were spotted among the Sargassum seaweed. The one above was found by Kim. This nudibranch feeds on other sea slugs, and sometimes, even others of its own kind!

Moon Snail (Natica zonalis)
While heading back to the main road, I came across this brown Moon Snail (Natica zonalis) - another animals which I had only seen a few times on Semakau too!

Doing hunting-seeking is certainly rather stressful and tiring, but yet at the end when you see how the visitors enjoyed seeing the things that you have found, it just makes you feel that it's all worth it! :)

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