26 December 2009

Colourful Chek Jawa with the Naked Hermit Crabs

Today, Ley Kun and I were out with a very sporting bunch of families for the free guided tour of the Chek Jawa boardwalk with the Naked Hermit Crabs.
The kids were very enthusiastic and sharp-eyed and spotted lots of interesting wildlife!

As we were climbing down the Tower, Jorryn our best spotter, points out a Golden orb web spider (Nephila sp.). There's a big hole in her web! But it looks like she has caught the vandal who is all wrapped up and ready for her next meal.
It was a sunny day so there were lots of insects about (besides the swarms of mosquitos). A pretty black butterfly, and Jorryn spots what seems to be the cocoon of an Atlas moth!
There were also several bright blue dragonflies in the back mangroves.
But the most abundant creatures that caught the kids' attention were crabs. Colourful but tiny crabs with red eyes!
Lots of Tree climbing crabs (Episesarma sp.), but they are hard to spot as they blend in with the mud!
And this looks like a little Face-banded crab (Perisesarma sp.)!
These fiddler crabs with stout pincers are also found in the back mangroves. There were lots of them in different colours!
Towards the coast, we see more of these different fiddler crabs. On the left, the Porcelain fidder crab (Uca annulipes) with a smooth enlarged pincer. On the right, the Orange fiddler crab (Uca vocans) with a pimply enlarged pincer.
Some parts of the shores were thick with fiddlers! Busy feeding and fighting.
Besides colourful animals, there were also colourful plants on Chek Jawa today. The Jambu bol tree (Syzygium malaccensis) was in full violent pink bloom! This fruit tree is commonly planted near kampongs, and is another sign of the old Kampong Chek Jawa from which the shore got its current name.
Earlier on, Ley Kun spotted the fallen flowers of the Sepuleh tree (Fagraea racemosa). It doesn't bloom all the time so it's really nice to see the pretty white flowers. These turn into green fruits. According to Burkill the plant is "much used by the Malays in medicine", and its name "Sepuleh" means "the restorer" in Malay.
And along the coastal boardwalk, the Delek air (Memecylon edule) are in bloom! These trees are listed as 'Critically Endangered" as they are rarely found elsewhere in Singapore. The rocky coastal habitats which they prefer are no longer common. The blue flowers are quite stunning. Although a bit far away from the boardwalk.
Visiting at an incoming tide like today allows us to see all kinds of marinelife that we can't see at low tide. Jorryn's dad spots a jellyfish! It is probably Acromitus sp.
He also spots this school of tiny fishes. I'm not sure what they might be. Perhaps some kind of baby Scats (Family Scatophagidae)? There was one with spots, and others with bands.
We also saw a huge school of small fishes swirling under the boardwalk. And Jorryn's dad also saw a stingray, he later told me. I didn't see it but here is Jorryn drawing it, and it seems to have a pointed head so it is probably the Mangrove whipray (Himantura walga).
I also saw mudskippers doing strange things today.

With all these fishes everywhere, the fishing birds are having a great time. We saw a heron stalking in the incoming tide. And Jorryn spotted one resting on the big dead mangrove tree in the middle of the lagoon.
At Changi Jetty, we spot two different kinds of Archerfishes. The pretty Spotted archerfish (Toxotes chatareus) has small spots between the broader bands, and golden eyes! It is not as commonly seen as the Banded archerfish (Toxotes jaculatrix) which only has big black spots and its eyes are not golden.
Jorryn's mum also showed me her photo of a feather star which she said they saw on an earlier trip to Ubin, clinging to wall at Changi Jetty! Wow!

Today, I saw lots of Ribbon seagrass blades (Cymodocea rotundata) floating in the water. During the mass deaths at Chek Jawa in 2007, I had noticed lots of Ribbon seagrass blades washed ashore, possibly as a result of lower salinity due to the high rainfall during the period. And on the way home, the water in the Straits seemed very brown, the colour of dark tea. I wonder if the rains have affected the area. Oh dear.

We should check out Changi beach soon just to be sure.

More about this trip on Fiddler crabs and madcap mudskippers at Chek Jawa
from Adventures with the Naked Hermit Crabs


  1. http://butterflycircle.blogspot.com/2008_04_19_archive.html

    The Common Mormon (Papilio polytes romulus)

  2. Thanks for the butterfly ID!

  3. Hi..I am Lay Keong who joined the walk on Saturday. Nice photos and documentation of the walk...your photos definitely do justice to the things we saw...in comparsion to those I took with my digital camera...made me want to change my camera :) Anyway thanks to you and Ley Kun for the wonderful time at P. Ubin.

  4. Thanks Lay Keong for dropping by the blog. I had a great time with everyone and the kids did all the hard work of spotting things! Although some were rather tiny, that's true.

  5. Hi, we missed this walk on boxing day! when will the next one be coming up?

  6. No worries about missing this walk, I'm sure we'll have more fabulous sightings at the next one. Every trip is a delight!

    We hope to have the walks every last Saturday of the month. Do drop by the Naked Hermit Crabs blog for more details, which should be posted up soon http://nakedhermitcrabs.blogspot.com/

    Hope to see you at the next walk!



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