14 June 2014

Moonlight survey of Chek Jawa coral rubble area

Under a full  moon in clear skies, a small team does our annual predawn survey of Chek Jawa
During a very low spring tide, we have a glimpse of some of the more delicate parts of Chek Jawa. How are they doing?


We are always glad to see Knobbly sea star! I saw these three large ones, but the team saw more. However, we didn't see any baby Knobblies.
Other sea stars I encountered included one Cake sea star and one Spiny sea star. There were a lot of Biscuit sea stars of all sizes from tiny to large. I also saw many medium sized Garlic bread sea cucumbers. There were many brittle stars which quickly retracted their arms into the crevices where they were hiding.
I came across about 10 white sea urchins on the coral rubble near the very low water mark. I didn't see any among the seagrasses. I have often wondered why there are a lot more white sea urchins among the seagrasses on Changi, but much fewer at Chek Jawa's seagrass meadows.
How nice to see the Spotted orange hermit crab. The last time I saw it here was in 2001.
Ivan found this hermit crab that we have not encountered before.
It looks somewhat similar to this one I saw at Tanah Merah in 2012.
I saw three little Reef octopuses. Two of them were stranded out of water. This one fortunately was still in a pool.
I saw a small Estuarine moray eel. This is a fish and NOT a snake. It has tubular nostrils, tiny eyes and no pectoral fins.
There are two Fan-bellied filefishes in this photo! I saw many of these fishes, mostly small.
This looks like a Black-spot tuskfish. My first time seeing it on Chek Jawa and I seldom see it. This fish is currently being considered for listing on the IUCN Red List of internationally threatened fishes.
Stranded at low tide were these small Black eeltail catfishes which were still alive although quite distressed. There were no nearby pools for me to transfer them to. Fortunately, the tide turns at sunrise and I'm sure they will be ok. I think Singapore's sea shores are so rich because our very low tides only occur in the dark. Otherwise, I can imagine many delicate marine animals will fry in the hot sun!
Here's some fishes I saw which I'm not sure of their identity. The rest of the team also found a live shark, which Dr Zeehan says looks like a bamboo shark. While Chay Hoon found a tiny Hollow-cheeked stonefish.
This Red egg crab was hiding in a healthy looking colony of Pore coral. The last time I saw this crab on Chek Jawa was in 2005. Chay Hoon found a Mosaic crab too, which I haven't seen since 2001. There were many colourful Swimming crabs of various kinds. Tiny and small shrimps of all kinds were busy on the shore including:Prawns (Family Penaeidae), snapping shrimps (Family Alpheidae) and various kinds of tiny shrimps.
This yet-to-be-identified Fine-lined flatworm seems particularly common on Chek Jawa. But today, only this one was found. Hopefully Rene will be able to sort out its identity.
There were a lot of Haddon's carpet anemones, especially in the seagrass meadows, but also on the coral rubble area. I didn't see any that were bleaching.
I also saw a Snaky sea anemone! My first time seeing this since we started the predawn surveys. The last time I saw this at Chek Jawa was in 2005.
I don't know what this pretty sea anemone is. I also saw one Tiger anemone, and many Swimming anemones.
I saw one small Ball flowery coral, and many Spiky flowery soft corals. One had Tiny colourful brittle stars. But I couldn't find any Ovulid snails.
There are corals at Chek Jawa! Many tiny to small patches of Zebra coral, but also small to medium-sized Boulder pore corals. I saw about 15 colonies. Kok Sheng says he saw about the same number as on his last survey in Jan 2014.
Some of the corals have a touch of coral bleaching, and one flowery soft coral was very pale pink.
There were many patches of these yet-to-be-indentified Posy anemones, as well as many small mounds of Button zoanthids.
There were some, but not a lot of seafans. I saw several  Candelabra sea fans, one small cluster of Tree seafan, two clusters of Skinny sea fans, and one Gnarled sea fan. I couldn't find any of the usual commensals on the sea fans (like snails or clams).
Among the lush seagrasses, I saw many Flowery sea pens. I also saw a few half-retracted Spiky sea pens. I also saw one Common cerianthid.
I saw one bunch of strange hydroids with flower-like polyps, and another bunch of stinging hydroids.
We were rather disappointed to see few sponges. The largest sponge I saw was this dark rose pink one which I have yet to figure out, I saw several of them. There were also several Yellow horn sponges and Yellow bumpy sponges.
I saw one cluster of Barrel sponge, a few clusters of Purple branching sponge, some black sponges but very few and small patches of other colourful sponges.
But most of the coral rubble area looked like this today.
This is what the coral rubble looked like when I last visited in Aug 2013.
Kok Sheng says the shores looked much better in Jan 2014 when the team surveyed Chek Jawa for possible impact of the heavy rains at end 2013.

The photo below is of the Chek Jawa coral rubble area before the sponges were wiped out by the mass deaths in 2007. This incident is believed to have been caused by heavy rain and Kok Sheng did a study of Chek Jawa's recovery.
Sponge garden at Chek Jawa in 2002
Sadly, I came across a trap under the House No. 1 jetty. There's also litter but not a lot. As well as large tyres. Although it was a relief not to come across a driftnet laid across Chek Jawa, like we did in July 2013.
The team last surveyed Chek Jawa in Jan 2014, I couldn't join them because I was still in a wheelchair from a broken foot. I was really glad to be able to walk again, although I still can't walk well in soft mud and can't walk very far.

More about the Jan 2014 survey:

Thanks to NParks for permission and support to do these predawn low spring tide surveys of Chek Jawa. Thanks also to Chay Hoon for making all the transport arrangements. And the team for helping to cover as much ground as we can during the narrow low tide window. Thank you!

More about why I think it's important to regularly survey Pulau Sekudu and Chek Jawa.

Posts by others on this trip

1 comment:

  1. Oh wow.

    I never knew we had so much going on in our coasts!
    I must try and join you guys sometime... It's spectacular.

    ReplyDelete

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