31 July 2015

Moonlight survey of East Coast Park

A small team returns to survey a sandy stretch of East Coast Park that has been taken over by seagrasses!
With the Bonnet snails and fig snails we saw, this shore reminds me of the Lost Coast.

There were lots and lots of small to medium sized Cake sand dollars!
Sand dollars are preyed upong by the Grey bonnet snail. Here's a half buried snail that appears to be sneaking up to a sand dollar.
Here's a look at the snail above the ground. Today I saw fewer and smaller Bonnet snails. Let's hope they are not being over collected on this accessible shore.
The Fig snail also eats sand dollars and other sand-dwelling creatures. Bonnet snails and fig snails are rather rare in Singapore because we have lost our flat sandy shores to reclamation. It's nice to see these animals returning to our artificial shores.
I finally found a small patch of live Button snails. On my trip here in Jan 2013 and Aug 2012, these snails were so abundant on large stretches of the sand bar that they were revealed in my footsteps on the sand! But today, there were not as many.
Moon snails are another fierce predator of Button snails. I saw this Ball moon snail moving about above ground (they are usually buried in the sand) and a small Lined moon snail. There were also many sand collars, which are the egg mass of moon snails.
Another predatory snail is the Olive snail. There were many of small Weasel olive snails on the sand bar. I didn't see any other kinds of Olive snails.
I only saw one Plain sand star (which is believed to eat Button snails) and one White sea urchin.
I saw a few of these Striped bead anemones. Also many Peachia anemones. Buried in the sand, I saw one Smooth sea cucumber, and several Acorn worms. As well as one Peanut worm.
In the sandy areas, I saw several Spotted mooon crabs. This one was in a pair. I often see this kind of pair of big crab holding onto a small crab. Are they getting ready to mate? Is the small one the male?
Today, the tide wasn't as low as on my trip here last month in Jun 2015, so I didn't get to see the seagrasses in deeper waters. But there was lush growths of broad Needle seagrass and Spoon seagrass with large leaf blades even at the mid water mark. There were some Crunchy pom-pom red seaweeds too. I only recorded seeing a tiny patch of Needle seagrass here in Aug 2012.
Among the seagrasses there were many small Swimming crabs of various kinds. I also saw one small Stone crab. I also saw a few small Orange-striped hermit crabs.
I saw one medium sized Mud crab. It was quite lively. Washed up on the tideline, I saw many large pincers that look like they belonged to Mud crabs. Were these crabs released on the shore?
Oh dear, was this Haddon's carpet anemone chomped on? Or has it tucked most of it oral disk into its body column? There was one anemone shrimp clinging on to the anemone. I didn't come across any of the usual colourful sea cucumbers that we see in seagrass meadows.
There was one other person with us on the shore and I could see him holding a large hand net and hear the rustle of a plastic bag and splashing of what sounds like a large fish in the bag. But I couldn't catch up with him to find out what was happening. We didn't come across any nets or traps and there was surprisingly very little litter on the shore.

Photo by others on this trip

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