Monday, February 9, 2009

Changi Beach with MGS girls

It has been quite a while I have visited this portion of Changi beach and this afternoon I was out with many girls from Methodist Girls School for a shore trip which aims to show and teach them about the ecology, biodiversity and conservation of sea shores.

I don't remember participating in such trips in the past, so these girls are really fortunate to experience wild marine life right here in Singapore.


Just at the high shores, the girls were amazed at the patterns of sand balls created.


The culprit of the sand ball formation is this sand bubbler crab (Scopimera sp.). The sand bubbler crab eats the thin coating of edible particles on sand grains by scrapping the food to its mouth. After which, the "processed" sand is then discarded as a little ball from the burrow entrance.

The crabs emerge as soon as the tide recedes. Therefore, you can estimate how long the tide has been out by the patterns of their sand balls. The more extensive the pattern of sand balls, the longer the tide has been out.


We walked towards the lower shore zonation and discussed about seagrasses versus seaweed and the uses of the flora in the sea. This is a seagrass (Halodule uninveris) because it has a root system unlike the seaweed.


Unfortunately, the Fern seagrass (Halophila spinulosa) seems to be affected by the recent scorching weather as they turn black in colour. Let's hope they can recover.


Another creature that excited the girls will be this Spotted moon crab (Ashtoret lunaris). Why were they excited? Because this crab can burrow into the sand in quick time.


Another sharp eyed spotting of the students will be this snail that has an anemone stuck on its shell. This is probably mutualism at work as the anemone can find a hard substrate to land on while the anemone helps to fend off predators of the snail with its stinging properties.


One of the girls spotted this tiny weeny green beachflea (Order Amphipoda) which I won't see because I am not really super detailed in finding creatures that don't have five arms. This beachflea is a crustacean that resemble shrimps. Most beachfleas are scavengers or feed on detritus. Some can filter feed. A few are predatory while some are parasites on larger animals.


The gong gong (Strombus canarium) is well known for being a seafood. It can be found in Changi but the population is dwindling because many people take them off the shores before they could replace themselves, which is probably unsustainable. Maybe one day gong gong may become even rarer to find? Food for thought indeed.


This is another gastropod, and a very big one that made the girls wow-ed. Yes, this is a very large noble volute (Cymbiola nobilis) that is unfortunately listed as 'Vulnerable' on the Red List of threatened animals of Singapore due to habitat loss, overcollection for food and its attractive shell.


It's my very first time seeing such a large razor shell or bamboo clam (Family Solenidae) which is about 8-10cm long! It's the kind of size you find in the seafood table since it is edible. It was really cool to see how the clam swim through ejecting a jet of water with its siphon.


The razor shell can even burrow and it showed us how it did it on the spot. After which, what remains will be this siphon that sticks out to the surface to breathe and filter feed.


I believe many students would have seen starfishes in photos or cartoons but this is the first time for many to see them alive! This is the plain sand star (Astropecten sp.)


More echinoderms were found including the salmacis sea urchin (Salmacis sp.) and many sea cucumbers like this Thorny sea cucumber (Colochirus quadrangularis).


One of the few special finds today will be this unidentified mysterious sea cucumber with "spikes" and circles on its body. It is relatively big, comparable some of the garlic sea cucumber.


The underside of the intriguing sea cucumber that we don't know what it is. It seems to have more spikey protrusions by the side. Another weird sea cucumber was also found by the students that is also as big and look like the Remarkable sea cucumber (Holothuria notabilis) but it is probably not because it also has quite obvious and longer spikey protrusions.

I'm always amazed at the diversity of sea cucumbers in Singapore. So much is unknown!


Under a rock was this weird looking creature that I don't know what it is! It is very small and has four pink stripes. Could this be a tunicate or sea squirt, or even a juvenile sea cucumber?


Another sighting will be this Dragonet (Family Callionymidae) fish that are well camouflaged and thus usually overlooked with the sand.


Another special find of the day! Henrietta found this pretty snail that I've not seen it before personally. This is likely to be a helmet shell from Family Cassidae (Thanks Ron for the id!).

This snail has two curved tentacles that come out from the centre, together with a siphon and a white mantle.


The underside reveals tooth like edges (not shown here) and a operculum looking structure at the end of its mantle to shut themselves off from predation or dessication.


Last but definitely not the least, one of the girls in my group showed me her find of this delicate looking Brown flatworm (Pseudobiceros gratus) and it is also my first time seeing this flatworm!

Today's trip with the girls was a fun one with many nice sightings and sharing about the different aspects of our own shore in Singapore. I hope they were motivated to express and act after exploring the living shore of Changi.

1 comment:

Ava said...

Hi, my name is Ava. Had a question to ask you but couldn't find your e-mail. Is there any way you can contact me? My e-mail is Charismaqueen100@gmail.com. It's about your blog.

Thank you!
Ava
http://www.thereeftank.com

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