Recce at Lim Chu Kang Mangroves 21/06/08

People present: Airani, Siva, Edward and me

A pity Airani cant join us in the mangroves due to an open wound, because I’ve heard of the story of her using a hand net to catch a Periopthalmodon schlosseri. It was supposedly bigger than 20cm!

After meeting at 8am at the Lim Chu Kang jetty, we walked past the rubbish-strewn coast at the front of the mud lobster mounds and headed in to the mangrove.

This mangrove is supposedly in its pristine conditions as little or nothing is man-made or artificially planted. The mud lobster mounds were big and numerous, supporting a healthy population there, I suppose. Afterwhich, we followed a stream, which opened into the sea, and headed into the mangrove forest. As compared to Sungei Buloh which is just “next door”, I am surprised by the canopy cover of Lim Chu Kang. The root system of the area has almost filled up the entire area except for the stream banks.

The burrows of larger sizes were found only next to the stream if there is a patch of area not covered by the pneumatophores. The smaller mudskippers were more readily seen and associated with the stream line while I really scratch my head about where are the bigger ones?

Since the giant mudskipper is a obligate aerobes, it would not be found in the burrows at low tide. All opportunities to stay emerged will be made use of. Are they out feeding when the tide goes out? If so, where? How come they appear at the openings of the burrow when the tide comes in? Are the burrows connected to the sea?

Before leaving the area we saw a Pn. schlosseri juvenile with a distinct black lateral line, about 6cm in length.

Then there was this 10-15cm thing that was right under our nose which I cannot identify cos the next movement caused it to jump into its burrow. I think it is a B. boddarti.

As tide rises, movement is seen at some burrows along the stream. The bigger size ones just popped back into the burrows as we go any nearer; there was a "school" of smaller ones which started appearing on the banks of the stream and were not affected by us as much.

As me and Edward were leaving the area, we went to the jetty to wash up. There we found a small number of small muskippers at the floating barrels. They were feeding on the barnacles on the barrels and we put one into the bottle since we are not sure what it is.

I learnt that on the mud, the mudskippers measure danger (us) more effectively than the ones we saw at Sungei Buloh when we were on the boardwalk.

Congeners and conspecificity

Congeners refer to organisms belonging to the same genus or species.

For two individuals to be conspecific, it means that they are from the same species.
Antonym: heterospecific

Reference:
http://en.wikipedia.org/wiki/Congener
http://en.wikipedia.org/wiki/Conspecific

Syntopic

To be syntopic means to be sharing the same habitat as another species and within their geographic range.

Reference:
http://www.practicalfishkeeping.co.uk/pfk/pages/glossary.php?entry_name=Syntopic

Allopatric speciation

Allopatric speciation, may also be referred to as geographic speciation, whereby populations of individuals are separated by a barrier and evolved such that when the barrier breaks down, these two groups no longer have the ability to interbreed.

"Allo" = other
"patra" = fatherland

Reference:
http://en.wikipedia.org/wiki/Allopatric_speciation

07/06/08 Recce at Pulau Ubin

Mr Siva, Maria and I were supposed to check out three sites - Sungei Ubin, Sungei Jelutung and the three bridges. However, the heavy thunderstorm made it really dangerous to venture out to the open area. Besides, we were with a group of Pedal Ubin participants so we had to observe safety.

We only managed to check out the mangrove patch at Sungei Ubin. We spotted larger mudskippers from afar and concluded that it may be the giant mudskippers (Periophthalmus schlosseri). After which, along the stream, I spotted a mudskipper that looked like silver-lined mudskipper (Periophthalmus argentilineatus) but it was really difficult to conclude.

So here's the picture of the fellow:


Then at the prawn ponds further in before the sluice gates, there were burrows of the giant mudskippers that made it look like a "schlosseri country".

That was one-third of Pulau Ubin checked. We will need another trip down.

An island of mudskippers

There was a find of an "island" of mangrove near as we walked out of Pasir Ris Park to the area nearing Downtown East and Toilet B. There were lots of silver-lined mudskipper
(Periophthalmus argentilineatus) in different sizes though they looked really different from the picture in the guide book.

06/06/08 Recce at Pasir Ris

We went for a recce at Pasir Ris Park in the morning and went into the mangrove boardwalk. Deep into the mangrove forest, we saw streams that seemed to be artificial and purposefully deepened. I guess this is to preserve the mangrove forest for the general public.

We spotted a lot of blue-spotted mudskipper (Boleophthalmus boddarti) , as well as giant mudskippers (Periophthalmus schlosseri). The blue-spotted mudskipper is more commonly seen in and along the streams. Another keynote was that the burrows did not have the telling ridges at the entrance of the burrows at Sungei Buloh had. Hence, it was difficult to tell the burrows from the tide pools. The density in this park of mudskippers was much greater than those in Sungei Buloh. Being confined to such small areas, they do not seem to display as much territorial behaviour as well, as compared to those at Sungei Buloh.


Map of Boardwalk at Pasir Ris Park