10 May 2012

Changi very much alive!

There's a lovely stretch of seagrass meadows and sandy shores on Changi that is similar to Chek Jawa. But it's only seen at very low spring tides.
Today I saw a Knobbly sea star, pink sand dollars and more! I also observed some interesting behaviour, including an awesome clam escape from a voracious predator!

I enjoyed a lovely sunrise, but the tide is still going out! Yes, the low tide happens about one hour later every day so there's still lots of work to do today! I haven't been here since August 2011, and I'm eager to know how this shore is doing.
I came across a small Knobbly sea star! We have seen these regularly at Changi usually in deeper water.
There were also many Plain sand stars (Astropecten sp.), and lots of Biscuit sea stars (Goniodiscaster scaber) big and small.
I saw a few Pink sand dollar (Peronella lesueuri), and saw the dead skeleton of a Laganum sand dollar (Laganum depressum) but I didn't see a live one. There were lots of Cake sand dollars (Arachnoides placenta), though I didn't find any of their spectacular snail predators.
There were plenty of White sea urchin (Salmacis sp.) out and about. These sea urchins 'carry' all kinds of things ostensibly for camouflage but also as a kind of umbrella to keep off harmful UV rays. I was greatly amused by the different things these sea urchins carried. Enormous empty shells, live sea cucumbers, and skeletons of other animals.
I also saw this strange white sea urchin with bright pink spines! I'm not sure if it's something different.
I saw a few Black sea urchins (Temnopleurus sp.), which also carry stuff. And one Thorny sea urchins (Prionocidaris sp.).
In the dark, this large Box crab (Calappa philgarius) actually waddled up to me. So far, I've only seen this crab on this shore.
I saw many large Haddon's carpet anemones (Stichodactyla haddoni), as well as some smaller ones which might be Tiny carpet anemones (Stichodactyla tapetum). There were also many Swimming anemones (Boloceroides mcmurrichi) large and small. On the high shore, there were lots of Peachia anemones (Peachia sp.).
I'm astonished to see plenty of Sea pencils on the shore today. This was just at sunrise. Later in the day, when the sun was high, they were nowhere to be seen! These burrowing creatures can retract into the sand.
Before sunrise, I saw several flowery sea pens (Family Veretillidae) and some cerianthids (Order Ceriantharia). I didn't see many of them again after the sun came up.
The seagrasses were lush with lots of Needle seagrass (Halodule sp.) both on the high shore and low shore. As usual, the dominant species were the Spoon seagrasses (Halophila ovalis).  The Fern seagrasses (Halophila spinulosa) seemed to be doing well. There were many of these small slender pipefishes among the seagrasses, but they are very well camouflaged and often overlooked. Sadly, I didn't manage to spot any seahorses today. We used to see them regularly here.
I also saw many Hammer clams (Malleus sp.). Today, I realise these clams actually bury themselves with the T-shaped portion beneath, sticking out the wavy tongue-like portion out of the sand. Those I see lying on the surface must have gotten uprooted?
There were lots and lots of Fan clams (Family Pinnidae) of all sizes. There's not a lot of hard surfaces on this shore, so the shell of the clam provides a home for a vast variety of creatures! Including colourful sea cucumbers,: today there seemed to be a lot more Pink warty sea cucumbers (Cercodemas anceps) than usual. Of course, the Thorny sea cucumber (Colochirus quadrangularis) were still abundant.  Sea anemones also settled on the clams. Snails seemed to be laying eggs on the inside of dead clams. Dead clam shells which are still half buried provide a safe home for small crabs too.
Also abundant on the shore today were Window pane clams (Placuna sp.) of all sizes, with many very large ones. These too provide a nice hard surface. I even saw Zebra corals (Oulastrea crispata) growing on them, and many had a small living scallop (Family Pectinidae) on them.
This empty Window pane shell was occupied by an Seagrass octopus!
Here's some snails I've never observed before. They are well camouflaged with a 'hairy' shell, but on the  underside has pretty patterns and a leopard spotted body!
The sandy shores here are full of life! Buried in the sand were lots of Ball sea cucumbers (Phyllophorus sp.) and Smooth sea cucumbers. I also saw some Olive snails (Family Olividae). James also found lots of other interesting marine life on the shore.
I saw this man drag an inflatable onto the shore, paddle it out and saw him checking a driftnet that had been laid parallel to the shore some distance beyond the low water mark. Perhaps it's the same man we saw on in July 2011, when we also saw a dugong feeding trail on this shore. I didn't see any feeding trails today.
Changi is an astonishingly rich shore, where even new records can be found. Let's hope it will remain rich and lush! I wish I could visit this shore more often, but there are not enough low tides to do all our shores!

My most astonishing encounter was with a clam that escaped a voracious predator. Here's more about it.

James has also blogged about the nudi and other special animals he saw.


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