Monday, February 09, 2009

First Semakau Walk of the Year

Finally, after a few months of rest, we had our first Semakau public walk for 2009.

It was an exceptionally good trip with lots of interesting finds - certainly a very auspicious start for our walks this year. Here's a quick listing of come of the things we saw.

As usual, I was able to find one of the long synaptid sea cucumber in the seagrass meadow.

We have not seen an ocellated sea cucumber (Stichopus ocellatus) for quite a few walks already, so it was really nice that one decided to show itself during our first walk of the year!

Yet another sea cucumber we saw was the sandfish sea cucumber (Holothuria scabra). This is one of the most valuable sea cucumber in the market, especially during the Chinese New Year period now.

Right after crossing the sea grass meadow, there was a huge population of sand-sifting sea stars (Archaster typicus). As the name implies, these are able to burrow into the sand to hide from predators and also to look for food. They feed on tiny organic particles among the sand.

And the star of the day is always the knobbly sea star (Protoreaster nodosus). We found 3 of them today. These brightly coloured sea stars can grow up to about 30cm wide, and is one of the bigger sea stars that can be found in Singapore.

And the special sea star we first spotted during the launch of Project Semakau also decided to make an appearance! We still don't know what species it is though.

This heart urchin (probably Maretia sp.) has a somewhat heart-shaped skeleton, thus its common name.

ST found a sea hare, which I have seen a few times on our southern shores, but still not really sure what species it belongs to. This was also the first time we found a sea hare during a walk too!

The black phyllid nudibranch (Phyllidiella nigra) is commonly seen on Semakau and our other southern islands. Nudibranchs from this family are said to able to release very toxic chemicals into the surrounding water when they are stressed.

The green ceratosoma nudibranch (Ceratosoma sinuatum) appeared to be in season.

It was really nice to see another "heart" after the heart urchin. This is a heart cockle (Corculum cardissa), which can come in various colours, such as orange, yellow, red and blue. Unfortunately, having such a pretty shape comes with a price, and they are often collected, cleaned and sold. Hopefully those seeking for tokens of love for their love ones will rethink about buying dead animals now that Valentine's Day is just round the corner.

There are lots of scallops in Semakau. These bivalves are able to swim by flapping their shells!

A much bigger bivalve will be our resident fluted giant clam (Tridacna squamosa), which can grow to about 40cm wide.

We found many noble volutes (Cymbiola nobilis) with their eggs today. Interestingly, I found a hairy crab (Pilumnus vespertilio) right in front of the volute, which somehow looked as if it was guarding the latter while laying eggs! Haha.

This spider conch (Lambis lambis) had a colony of Porites coral growing on its shell. I wonder if one day the coral will outgrow the shell?

Another mollusc we saw was this squid (Sepioteuthis sp.), which could change its colour to blend into its surrounding. I also found an octopus, but unfortunately was unable to grab a shot before it disappeared.

The upside-down jellyfish (Cassiopea sp.) appeared to be another animals which was in season. These jellyfish has symbiotic algae living it its tentacles, and thus it is usually found swimming upside-down to expose the algae to the sunlight for photosynthesis. Some of the food made by the algae will be passed on to the jellyfish.

The relative of the jellyfish, the hard corals, can be found in a wide variety on Semakau. Many people have probably seen this staghorn coral (Acropora sp.) while snorkelling at our neighbouring countries. It can be found on Semakau too.

Corals come in various growth form other than the branching form. This purplish boulder is actually a Porites coral!

Most of the corals we see are colonial animals, and the Pocillopora coral above is home to thousands of little coral animals known as polyps.

This soft and fleshy looking clump is also a hard coral, Euphyllia ancora! It has a hard skeleton underneath.

Not all corals live in a colony though, and some of them, like this sunflower mushroom coral (Heliofungia actiniformis), is one single animal.

Apart from the hardies, we have the softies too. Here's a colony of soft corals. The greenish ones are those with the polyps extended, while the pinkish ones are the ones which the polyps have retracted.

There were quite a few magnificent anemones (Heteractis magnifica) in the intertidal area of Semakau. Unfortunately, I did not see any anemonefish in the one above.

The bulb tentacle anemone (Entamacea quadricolor) can also be found at the reef crest.

One of the less common anemone, Heteractis crispa, which so far I've only seen on Semakau. I've seen at least 3 of them at various locations over the past 3 years.

Anf of course, we have the usual gigantic carpet anemone (Stichodactyla gigantea), and this one has an anemone shrimp (Periclimenes brevicarpalis).

Talking about shrimps, we should forget about their relatives - the crabs! There were lots of porcelain fiddler crabs (Uca annulipes) near the mangrove area, and the male crabs were busy waving their big claws, probably trying to catch the attention of the females!

We also found a few of the Acanthozoon flatworms.

And I also managed to find a tigertail seahorse (Hippocampus comes) at the site which I usually found them!

Certainly, today was a great start for the year. Looking forward to more great trips with lots of special finds for the rest of the year!

1 comment:

ChrisM said...

Your unknown species (the one next to the Maretia urchin) looks like its probably the "adolescent" stage of Cucltia novaeguineae. That is, just after the "cookie" stage but just before the adult. I'd need to see more pix to be sure...but it does look like the papulae patterns are right...