Pulau Ubin on 22/07/08

People present: Maria, me
Tide: Rising to high

Time and tide waits for no man.

I reached Pulau Ubin when the tide is rising. Enough said.

The worst thing to commit when looking for mudskippers. Mid-tide is alright, but when we reached Pulau Ubin as the tide is rising, it is clearly impossible to recce all the different sites to check what is where.

I managed to get to Sungei Ubin before, so I knew that there are B. boddarti and Pn. schlosseri at the prawn ponds beyond the sluice gates. But when I reached there on my rented-for-$5 bike, the only mud flats exposed are beyond the power of the Opticron binoculars to be able to distinguish any mudskippers apart. However, I did see one Ps. walailakae above 10 in length a mere metre before me. There also about 5 other small ones in front of me but I was too engrossed with the large one.

I tried to go to the three bridges overlooking Sungei Mamam but the trail is closed to public!

Then Sungei Jelutong which was our last stop was obviously at high tide when we reached there.

SBWR Mangrove Arboretum on 21/07/08

People present: me
Tide: mid-tide to rising tide

One thing I learnt from this recce may be that there may be some form of habitat partitioning between Periophthalmus walailakae and Periophthalmodon scholsseri after all. At the Mangrove Arboretum, on the boardwalk from MA1 to MA2, there are many Pn. schlosseri seemingly "basking" themselves in the open. There were only 3 Ps. walailakae in more sheltered area in between MA1 and MA2. After MA2 in the covered canopy area where many tree-climbing crabs are roaming freely, there are more of the smaller burrows as well as their owners - Ps. walailakae.

Pn. schlosseri is also seen to be feeding, doing burrow maintenance as well as displaying territorial behaviors.

LCK recce on 19/07/08

People present:
Edward, Theresa

The mangrove in Lim Chu Kang has a shape like that of a rectangle framed by the coast and fences that act as a barrier between the mangrove and the part of the mangrove that has been cleared away for farm use.

The Lim Chu Kang mangrove is also just adjacent to the Sungei Buloh Wetland Reserve, found in the Northwestern coast of Singapore.

We spotted many small and beautiful Boleophthalmus boddarti and Edward also caught one in his hand net. Feeling our presence, they also flared their pretty yellow dorsal fins at us. In addition, we saw countless Periophthlamus walailakae as well, with the largest one spotting a size about 15 cm long!

Just as we get really fired up trying to catch the mudskippers using stalking, trapping, cornering methods, it had to start raining. Coupled with the fact that the tide was already rising at about 1030a.m., we decided to call it a day. Then we found out that it was a real good idea since the stream where water flow came in from was already more than 1 metre wide, meaning the tide is slowing filling the mangrove bed.

Ps. when the tide is rising and there is rain, try to evacuate asap as it will mean tide will be rising faster than expected.

SBWR recce on 25/06/08

The Mangrove Arboretum



The low tide for that day was at 11am but the time at which we were let off from our fieldtrip was about 1pm. Basically, there was a race against time to check out the mudskippers at the Mangrove Arboretum Boardwalk.

Armed with a camera which has zooming power much left to be desired and a pair of binoculars, I spotted more than 20 Periophthalmodon schlosseri just from MA1 to before MA2! Comparatively, there were lesser of Periophthalmus walailakae (like only 2!).

After which, the tide rose, period.

Ps. the mudskippers spotted were those nearer the boardwalk.

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