30 May 2017

Signs of dugong at Changi

After a rain storm, we survey the large expanse of Changi's seagrass meadows during a super low tide. The seagrasses are lush and thick. We saw lots of dugong feeding trails!
Living seagrass meadows at Changi
I heard that this shore was affected by the 300-tonne oil spill in the East Johor Strait in January. I didn't see any signs of oil today and was glad to see many of the usual animals.

Dugongs eat seagrasses (and hence sometimes also called sea cows). They leave a typical trail when feeding in a seagrass meadow. A band of bare sand of equal width, somewhat meandering. There were many such trails visible today in the very low tide.
Dugong feeding trail in seagrass meadows, Changi May 2017
Some of the trails were exposed briefly above water.
Dugong feeding trail in seagrass meadows, Changi May 2017
Here's a brief view of the large extent of the seagrass meadows, exposed on this super low tide today.
Seagrass meadows at Changi
The meadows comprised mostly of Spoon seagrass (large and small leaved) with some Needle seagrass (mostly narrow, but I saw a few clumps of broad leaved ones) and some patches of healthy looking Fern seagrass. I couldn't find the patch of Smooth ribbons seagrass, but they might still be there, I just overlooked them.
Seagrass meadows are home to all kinds of animals. I saw this small green filefish that looked just like a seagrass blade, and a small solefish.
Later on, we saw a Cowfish!

As usual, the most abundant animal on the seagrass meadows are sea cucumbers. Dominating the shore were many Thorny sea cucumbers and Pink warty sea cucumbers. There were also many Orange sea cucumbers, some Purple sea cucumbers. I saw one small Garlic bread sea cucumber and a Smooth sea cucumber and a few Ball sea cucumbers.
In fact, Changi is full of spectacular echinoderms such as sea stars. Today, we saw many small to medium sized Knobbly sea stars. There were many tiny to small Biscuit sea stars. I saw one Common sea star.
There were also some White sea urchins (I saw about 10 small to medium sized ones), many Flat-armed brittlestars and I saw one feather star.
There are lots of Haddon's carpet anemones on the shore.
Living seagrass meadows at Changi
Most the Haddon's carpet anemones were alright, but I saw two that were very pale.
Other anemones seen included one Swimming anemone, one Big hermit-hitching anemone, some Tiger anemones, one Mini carpet anemone. Dr Sergio was with us and fortunately we found a few cerianthids that he found interesting. But this shore doesn't have many of them.
Other critters seen included some Orange-striped hermit crabs, a few Flowery sea pens, some Acorn worms. And many clumps of these lacy white things. I'm not sure what it is.
I didn't see any living Noble volutes, but did see one of their egg capsules that looks like the babies had hatched. There were many Hammer oysters. I saw some pink egg strings but couldn't find any sea hares. The only slug I saw was an Ornate leaf slug.
Recent surveys by others at Changi reported seeing the Clear sundial snail, which we have seen only in the South so far. I saw one today, laying eggs.
Sundial snail (Architectonica perspectiva) laying eggs
Why are  these snails suddenly appearing at Changi? Did they come in with the sand that is being used to reclaim Tekong?

We had planned to survey the seagrass meadows at Changi Point. But we got word that a huge excavator was seen yesterday ripping out old pipes there, probably causing extensive damage to the shore. Marcus and Kok Sheng checked it out today and saw many injured Ball sea cucumbers. These sea cucumbers are usually buried.

Photos by others on this trip

On 28 May, Loh Kok Sheng and some of the team visited this shore at Changi and saw some awesome marine life! Jianlin Liu and Jesselyn Chua were also on the trip.

Victor Toh was also at Changi. And saw traces of oil in his footprints.

On 31 May, Chris Wong surveyed Changi bay next to the Ferry Terminal and shared what he saw.


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