19 February 2019

Clam takeover at Changi

Clams have taken over most of a stretch of Changi beach, forming a dense firm mat.
Unidentified clam (Family Mytilidae)
There is also suddenly a lot of Fan shell clams, as well as Window pane shells. But there is still good seagrass cover, and some of the usual animals are still abundant.

It was alarming to see that much of the shore has been taken over by these clams. I don't know the identity of the clam, but I have seen this before on some of our other shores, though not in such dense mats. These do not look like the invasive clams that took over at Kranji.
Unidentified clam (Family Mytilidae)
Here's a video of the extent of the clams. I'm not really sure what is happening.
Unidentified clam (Family Mytilidae)
There is suddenly also a lot of Fan shell clams, similar in size, so perhaps of the same age?
Fan shell clam (Family Pinnidae)
Here's a video of the Fan shell clams.
Fan shell clams (Family Pinnidae)
There was also a lot of Window pane shells. I did notice many small Fan shell clams and Window pane shells during our last survey in Aug 2018.
Window-pane shell (Placuna sp.)
I also saw a few other clams that I don't often see. There were also many Hammer oysters.
There were also many snails. I saw several Noble volutes, some Gong gong and Black lipped conch, one Miliaris cowrie. Kelvin spotted the empty shell of a Baler snail, we saw a live one here on our last survey in Aug 2018. There were lots of egg capsules including some sand collars. I didn't see any live Babylon snails, but did see a shell occupied by a hermit crab.
I only saw one Biscuit sea star and couldn't find the Common sea stars. I saw a few White sea urchins and Black sea urchins, all small. There were a lot of young Garlic bread sea cucumbers, and lots of Thorny sea cucumbers and Pink warty sea cucumbers. I saw one Ball sea cucumber. There were also lots of little elbow crabs, tiny Flower crabs.
Jianlin saw a large Knobbly sea star.
There were also many Haddon's carpet anemones and I saw one Geographic sea hare. Here's a clip of some of the marine life on the shore.
Living shores of Changi, Feb 2019
When we see a leaf or shell or debris 'walking' around, it usually means there's a Leaf porter crab under it!
Leaf porter crab (Family Dorippidae)
The seagrasses are still growing well on this shore. I came across lots of Spoon seagrass, Fern seagrass and Needle seagrass with narrow leaves. For the first time, I saw a lot of Needle seagrass with broad leaves. But I didn't see the Smooth ribbon seagrass and Noodle seagrass that I saw during our last survey here in Aug 2018,
There were a few people on the shore with plastic bags collecting marine life. We did not come across any traps or nets.
People collecting marine life on the beach
How strange to see lots of golf balls here.
Marine litter on Changi Beach
The high shore is cleaned every day so there isn't much litter. As usual, many mangrove seedlings wash up here, including some rarer species.
Various mangrove seedlings washed ashore
This Changi shore can change very drastically between our surveys. I hope it remains safe until we can return again.

Photos by others on this trip

Jianlin Liu

Kelvin Yong

Meanwhile, Richard Kuah surveyed Coney Island on 18 Feb and the shore looks good.


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