Thursday, September 4, 2008

The lord of the mudflats

I found out the reason as to why Periophthalmus walailakae has been mistaken to be Periophthalmodon schlosseri today.

Apparently, the distinguishing black lateral stripe coursing posteriorly down Periophthalmodon schlosseri was believed to be a display that is shown only when the mudskipper is agitated or threatened.

Reference:
Murdy, E. O., 1986. Mudskippers of Malaysia. The lords of the mudflats. Freshwater and Marine Aquarium 9:20-23.

Personal communication with Prof Ip

Important take home message from a brief exchange (I went to borrow a book from Prof Ip):

1. The secondary fused lamellae of the gills of Periophthalmodon schlosseri is a telling difference should I find it difficult to tell it apart from another species.
(Problem is, I have not been able to even lay my hands on one!)

2. When a mudskipper "disappears" into a burrow, it is not necessary its own.

themudskipper.org

An informative website by Gianluca Polgar.

The species list taught me about the genera of mudskippers I am working on. Periophthalmodon has three species while Periophthalmus is the largest genus from the subfamily of Oxudercinae, with 17 species.

I love the applet (?) of a mudskipper on his site. It actually displays its dorsal fins!

Pandan mangroves 04-09-08

Pandan mangroves is a thin strip of what was left after the completion of Pandan Reservoir. It is only a 15 minutes drive from National University of Singapore, along Jalan Buroh, which is good news for me if I am intending to tap into this source for Periophthalmodon schlosseri.

The back mangrove that is near to the road, and where a small stream flows consistently, a microhabitat containing many juvenile Periophthalmus argentilineatus is spotted. Further down the stream is where Paul, Marcus, Danny and me wait in anticipation to scan for any movement from the "wanted species number one" --- Periophthalmus walailakae.

When the tide was coming in today, we discovered the hot spot for "wanted species number two" --- Periophthalmodon schlosseri. I have yet to catch any of this species. Sigh. Mind you, we tried cast nets and tow nets today, on top of long hand nets.

Next up, weaving lessons for me (to make a trap).

Ps. Pandan mangrove smells bad; but Lim Chu Kang will always be my first love, not.

Saturday, July 26, 2008

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.

Sunday, July 20, 2008

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.