Saturday, June 25, 2011

Pulau Semakau (25 Jun 2011)

A small team removed a long abandoned driftnet at Pulau Semakau today.
The net was 48m long when we measured it with the tape. But including the bunched up portions, it's probably about 50m long.

We learnt of this net from Lim Jiayi who spotted it last week. At that time, she saw a large fish trapped in it. We didn't see any fishes trapped in the net today. Thank you Jiayi for the alert!
Photo by Lim Jiayi
But a small Mud crab (10cm across) (Scylla sp.) was trapped in the net. It has lost one of its pincers.
Here's a look at the underside of the crab. Probably a female?
Brandon and Andy carefully snip out the crab.
Here's a closer look at the delicate task.
Jerome is documenting the process. Thanks Jerome!
Andy also finds this crab (6cm across) with yellow spots on its belly. It's probably Ozius guttatus and a male crab.
A large sponge (about 50cm across) was also entangled in the net. Probably from the reefs much further down the shore as these sponges don't grow on the high shore.
Another smaller sponge (about 30cm across) is also entangled in the net . This strange organism is a combination of a sponge and a seaweed! The seaweed experts call it Cladophoropsis vaucheriaeformis and the sponge experts call it Halichondria cartilaginea. The sponge cells and spicules are intertwined with those of the algae. Again, this also grows in deeper water.
The net had also entangled and nearly uprooted a small mangrove tree. An egret landed nearby while we worked. Shorebirds who approach animals trapped in a net might also become trapped in the net. Abandoned nets can cause all kinds of tragic damage and it's good to remove nets as early as possible.
While the gentlemen cut up and 'wash' the net (to leave behind all small organisms and seaweeds stuck on the net), I head out West to check up for more abandoned nets. Fortunately, I didn't find any.
We then headed back East to rejoin Dr Daphne and Nicholas who were looking for anemones. We came across more abandoned nets stuck among the mangroves there and removed a few.
The nets seem to have been there for a while. Fortunately, we didn't come across any animals entangled in them. As Andy suggested, we should come back again to clean up the mangroves of these nets.
The haul for the day included lots of long plastic entangled in trees.
After clearing up the nets, we had a quick look at the rest of the shore and found a Critically Endangered Api-api jambu (Avicennia marina), then later joined Dr Daphne and Nicholas who were looking for sea anemones. More about this on the wild shores of singapore blog.

Thanks to Mr Tahir for taking us out and bringing us back for this trip. And Jinny and friends at NEA for permission to visit to get this job done.

Thanks to Lim Jiayi for the alert on the net. And special thanks to Brandon, Andy and Jerome for removing the net!

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