24 June 2013

Gomeza Bonanza at Changi

The finds of the day were these little crabs that are easily overlooked as hermit crabs in a round shell (which are abundant on this shore).
Although there were many other first-time finds for us, many animals were also 'missing'. Is this special seagrassy Changi shore changing?

The Masked burrowing crab (Gomeza bicornis) is rarely seen as it hides in its burrow. Because we know the museum is keen to video these crabs in action, we were on the look out for them. And today we found six of them just sitting above ground. We have no idea why.
The current hazy conditions sparked Kok Sheng to come up with this amusing caption! Read more on his blog.
Photo by Loh Kok Sheng.
Another special find is another 'brown peachia'. This will be useful to Nicholas Yap as he needs more specimens to be sure that this animal is indeed a new species! How nice that the species will be described from those found in Singapore.
Here's what the anemone looks like before I took a closer look at it. We also found one in another part of Changi a few days ago.
This part of Changi has lush seagrass meadows teeming with life! On this trip, I saw many Striped hermit crab (Clibanarius infraspinatus) (orange arrow), many Plain sand stars (Astropecten sp.) (yellow arrow), many Hammer oysters (Malleus sp.) (blue oyster) almost all of them with the tongue-shaped portion sticking up. There were also many more Pink warty sea cucumbers (Cercodemas anceps) (pink arrow) than Thorny sea cucumber (Colochirus quadrangularis). Usually, it's the other way around.
The other super abundant animal today were White sea urchins (Salmacis sp.). They were everywhere. I didn't see any other kind of sea urchin today.
I also saw many large shells of dead Razor clams (Family Solenidae). Are there many more living ones still buried in the sand? Many animals live in the sand and what we see during a short low tide on the surface is just a tiny fraction of the biodiversity that can be found on a shore.
I saw several seagrass pipefishes. These fishes seem to be seasonally common in the seagrass meadows. Do the pregnant papas come to the meadows to release their live babies? Like their cousins the seahorses, the male pipefish keep the eggs in a pouch on their bellies.
A night trip is a great time to spot fishes as they are less flighty. Today I saw many Smallhead dragonets (Callionymus erythraeus), several tiny Kite butterflyfish (Parachaetodon ocellatus) and a small goatfish (Upeneus tragula).
This tiny filefish (Family Monacanthidae) looks so much like a blade of seagrass, that even the Rabbitfishes (Family Siganidae) flatten up next to it.
There are many large fishes which are well camouflaged. Like this Fringe-eyed flathead (Cymbacephalus nematophthalmus).
This one is not a flathead. It is probably the Crocodile flathead goby (Psammogobius biocellatus).
There were also several of these Commerson's sole (Synaptura commersonnii).
Another abundant but well camouflaged creature found here are these green prawns (Family Penaeidae). There were also lots of Flower crabs (Portunus pelagicus) and Spotted moon crabs (Ashtoret lunaris). Also well camouflaged Elbow crab (Family Parthenopidae). Chay Hoon found a Pebble crab (Family Leucosiidae) and I saw a Leaf porter crab (Family Dorripidae).
I came across this hermit crab outside it's shell! It promptly stuck its butt back in when I took a closer look. I have no idea what is going on. Perhaps it was getting ready to moult?
Kok Sheng found this special snail that I've never seen before. Tan Siong Kiat of the Raffles Museum is in the process of writing a paper on this, so he's very grateful for a look at this snail. Singapore's shores are still full of suprises and discoveries to be made.
This is another strange snail. It looks like the very commonly seen Spiral melongena (Pugilina cochlidium), but this snail has a longer pointy part (siphonal canal) and the body is not very black. Hmm...
We didn't see any live Baler snails (Melo melo). But there was a large shell of a dead one. It was occupied by an Seagrass octopus!
I also came across a strange little octopus. It was maroon with white spots. I remember seeing something like this a long time ago on Beting Bronok.
When submerged, this large cockle has frilly tentacles sticking out the shell opening! There were many large living Window pane clams (Placuna sp.) all over the seagrass meadows.
I only saw one  Pink sand dollar (Peronella lesueuri), unlike in Aug 2012 when we saw lots of them here. Although there were some ordinary Cake sand dollars (Arachnoides placenta). Unlike in the past, and other parts of Changi just a few days ago, we didn't see many kinds of sea stars here today. I saw only a few Painted sand stars (Astropecten sp.) and one Biscuit sea star (Goniodiscaster scaber). In the past we used to even see Knobbly sea stars here.
For the first time, I saw an Oval moon snail (Polinices mammilla) on Changi. These are common in the South, in the north, the Ball moon snail (Polinices didyma) is more common. I also saw several Pink moon snails (Natica zonalis) and one large moon snail that looks like a Naked moon snail but which Siong Kiat has pointed out has an operculum and is a moon snail. Possibly the Bosom moon snail (Polinices mammatus)?
I saw one Orange sea cucumber, several large Garlic bread sea cucumbers (Holothuria scabra), many Beige sea cucumbers and one Remarkable sea cucumber (Holothuria notabilis). There were many Ball sea cucumbers (Phyllophorus sp.) and Smooth sea cucumbers.
Also a first encounter on this Changi shore was a Miliaris cowrie (Cypraea miliaris). I saw the strange Mitre snails (Family Mitridae) that we started seeing since our trip in Aug 2012. There were some Olive snails (Family Olividae) and many Noble volute (Cymbiola nobilis) of all sizes.
I saw several Big hermit-hitching anemones stuck onto Fan clams instead. This one was fully expanded, with its short and long tentacles facing in opposite directions. Other sea anemones seen on this trip was one Tiger anemone, a Glass anemone (Dofleinia sp.). I saw one Ball flowering soft corals (Dendronephthya sp.), a few Flowery sea pens (Family Veretillidae), Common sea pens and Spiky sea pens, Slender sea pens (Virgularia sp.). There were many sea pencils. As usual, there were only a few cerianthids (Order Ceriantharia) here.
There were a few large Haddon's carpet anemones (Stichodactyla haddoni). Those in the north are usually teeming with tiny anemone shrimps (Periclimenes sp.). I don't see these tiny shrimps on the carpet anemones in the south. Another mystery of our shores.
The seagrasses were lush and well. There were lots of healthy Fern seagrass (Halophila spinulosa), large leaved Spoon seagrass (Halophila ovalis) and Needle seagrass (Halodule sp.) everywhere. I saw a few furrows that looked like dugong feeding trails but it's hard to be sure in the dark. I got the sense that the sand bars have moved and the shape and structure of the lagoons have changed. It's hard to tell in the dark.
I noticed that many of the Fan clams (Family Pinnidae) were heavily encrusted with thick layers of ascidians of various kinds. Is the sudden 'bloom' of ascidians a result of changes in the water? I noticed massive works at the park area in Aug 2012 and was worried about sand being piled on the beach to 'replenish' it.
There were indeed several changes observed today by the team, compared to the past, as well as to nearby Changi shores visited a few days ago. Hopefully, this stretch of seagrassy Changi will recover. The fact that the other nearby Changi shores seem unchanged, means these shores can help provide the babies and seedlings that can help with the recovery.

Tomorrow, we explore the artificial shores of East Coast Park which had surprised us in the past.

Posts by others on this trip
  • Mei Lin with more interesting critters.
  • Kok Sheng with more about the special crab and other finds.
  • Pei Yan with great photos of these special animals.


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