10 January 2010

Dead Fish Patrol: Chek Jawa, Pulau Ubin

Are there any dead fish at Chek Jawa and Pulau Ubin?
A few of us spent this scorching hot day to find out.

The first dead fish we saw was on the excellent Nasi Lemak at Pak Ali's shop. Fortified with Ubin lontong and other local favourites, we headed out for Chek Jawa.
At the Chek Jawa boardwalk, we saw lots of interesting fiddler crabs, fishes (very much alive) and mangrove plants.

But didn't see any dead fishes. Andy had a good point, the waterline is well patrolled by wild boar (Sus scrofa) which would have eaten up any dead fishes washed ashore. We could see the well 'ploughed' area of the waterline where the wild boar have been busy.
The seagrasses of Chek Jawa are doing very well! Chek Jawa has one of the few large patches of Smooth ribbon seagrass (Cymodocea rotundata). And the patch seems just as large as when we last saw it.
Here's a closer look at the meadow of Ribbon seagrass.
Seagrasses provide shelter for all kinds of animals. The tide was low enough for us to see some animals such as a Noble volute (Cymbiola nobilis) and a large Striped hermit crab (Clibanarius sp.). And yet the tide was high enough for us to see some fishes such as these baby Spotted scats (Scatophagus argus).
And all this yummy fishes attracts hunters such as this large heron. I'm not sure if it's the Great-billed heron or the more common Grey heron.
It caught something! Is that a bit of seagrass with its catch?
The bird was surprisingly close to the boardwalk. A situation that didn't last very long as a bunch of kayakers got real close to the shore and frightened the bird away. Here's a closer look at the bird and kayakers in the big photo.
Later on, I saw some windsurfers come close to the Chek Jawa shore too.
I never really noticed the fish farms off Pulau Ubin until now.
There are quite a lot of them, and some are close to Chek Jawa.
Here's a view of the long line of fish farms all along Ubin's northern shoreline stretching from the people on the Chek Jawa jetty to the red-roofed Ubin jetty in the distance.
After completing the boardwalk, we checked out a short section of the shore west of Chek Jawa. There was a very thick carpet of sea lettuce seaweed (Ulva sp.) piled up on the shore, crisping up in the sun.
And on the high shore, we saw a half dead eeltail catfish (Family Plotosidae). We gently put it into a piece of plastic (catfishes have venomous spines and should not be handled), and released it into deeper water. At first it was listless, then finally it started to swim off into deeper water.
Further along we found half a dead eeltail catfish.
Other than these two sightings, we saw no other dead fishes large or small.

The seagrasses on this shore are doing well too. There were lots of large big Spoon seagrasses (Halophila ovalis).
And small patches of the rare Beccari's seagrass (Halophila beccarii). This tiny seagrass doesn't look like much when it's plastered on the sand.
But a submerged portion shows how the tiny little leaves emerge in a rosette of about five long narrow leaves.
Off the Pulau Ubin shore is the little island of Pulau Sekudu.
Pulau Sekudu means 'Frog Island' and there is indeed a large rock in the shape of a frog on this island.
There are also lovely natural rock formations on this island. As well as lots of marvellous marine life. Here's other posts and more photos about Pulau Sekudu.
Alas, we saw several clumps of freshly abandoned driftnets on the Ubin shore, opposite Pulau Sekudu.
As well as some clumps on the high shore too. These nets continue to trap and kill marine life as long as they remain on the shore.
We know they are freshly abandoned as International Coastal Cleanup already cleared this site in Sep 09. The problem of marine debris is a never ending and heart-breaking one.
Another heart-breaking encounter was just as we started at the Chek Jawa boardwalk. We saw a group of monks and their supporters walking down to the boardwalk carrying two large plastic bags full of frogs which they bought from pet shops (the frogs are probably intended for feeding carnivorous pet fishes). I stopped the group and explained why the frogs would die if they were released into the sea.
The group eventually went away and said they would release the frogs in freshwater. While this may not kill them, the released frogs may then kill existing wildlife in the area. The practice of animal release often does more harm than good. Here's more details.

On the walk home, we also saw some Jungle fowl (Gallus gallus) foraging in the forest, and James spotted a Paradise tree snake just as the van arrived. I didn't take a good photo of it, but James has a great one on his blog post. And Andy took a fabulous video clip of it.

On the boat ride home, the water seemed a bit brownish but not as brown as when I last saw it.
I also took some photos of the fishfarms near Chek Jawa.
This one with large buildings was the closest to Chek Jawa.

Separate posts on some of the interesting encounters we had of fiddler crabs, mudskippers and mangrove plants.

See also Jame's post of the trip on his Singapore Nature blog. And Andy's video clip of the paradise tree snake on his sgbeachbum blog.


  1. Great to read that Chek Jawa doesn't seem badly affected, unlike Pasir Ris.

    Those are some excellent shots of the great-billed heron in action.

    We seriously need to do something about all these releases. Don't tell me the rangers need to look out for groups of devotees releasing animals in Chek Jawa? Sigh. I guess those frogs they were releasing are young crab-eating frogs, which are native, but I still doubt many of them would survive. Or that those that do survive might end up spreading diseases to the wild amphibians (if I'm not wrong, these frogs are raised in large numbers on fish farms). I would be very upset if some idiots released American bullfrogs into Chek Jawa.

  2. Thanks for the bird ID Ivan.

    Yes, the attempted release was disturbing. It is a difficult issue to handle.



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