Tuesday, September 22, 2009

St John's Island Guided walk

It's time to set off for a guided walk! It's been three months since I've guided on our shores during low tide. And our destination for the day is St John's Island.

On our way there, the ferry made a turn that was very near the man-made structure where Kias reef used to be before it was buried and reclaimed to be connected to Lazarus for developmental purposes. This is also the spot where we have seen marine turtles before.

Our first stop was to Tropical Marine Science Institute (TMSI) for a short tour. It's also a place where I spent one year there doing my final year project.

What a treat to see the white peacock again! As previously shared in my post, the white peacock is not an albino but their pigment is due to a colour mutation.

The participants were fascinated by the shell collection at the admin building as well as the outdoor aquaria where corals, sponges and giant clams are kept for research purposes.

I shared with them about larvae that can still infiltrate through the filter system into the tanks and the classic example will be the swimming crab feasting on Mei Lin's giant clams. Many of us were both shocked and amused to hear about that!

After a short rest, it was time to proceed down to the shores!

And guess what, my darling leopard cat came to greet me. must be hungry over the long weekend!

He is my most favourite cat of St John's Island. Sad to see though was that he has grown skinnier! :-(

Finally we reached the sandy lagoon where the seemingly barren shore is filled with life for all to marvel at. There were different types of animals around.

One of the most interesting finds by the hunter seekers will be this swimming crab that has an unique pattern. I've never seen this before.

This pair of snails are the Oval moon snail (Polinices mammatus).

Moon snails are fierce predators, feeding on bivalves and snails. A moon snail wraps its huge body around the hapless prey to suffocate it. If this fails, it has a gland at the tip of its proboscis that secretes an acid to soften the victim's shell. With some help from its radula, a hole is created.

Edmund, one of my group's participant found a tiny star. His eyes are really keen! Upon closer look, I realized it's a Common sea star (Archaster typicus)! And probably the smallest I've ever came across. Of course, stars are attractions for the younger ones. Though we have to quickly put it back into the water before it gets stressed.

Of course, our hunter seekers found pairs of adult common sea stars in a mating position. They do not mate directly but release their eggs and sperms for external fertilisation.

The most exciting part of St John's shore must be the natural reefs! It's definitely not advisable to visit it when it is not a low spring tide due to the strong currents.

The natural reefs are filled with pinkish rocks at the high shore. Many of these rocks have fracture lines, indicating the presence of wave action over the years.

There are many different types of hard corals on the reef and I specifically shared with the microalgae or zooxanthallae that is able to make food for the corals as well as the terrible effects of global warming which will lead to coral bleaching.

There's a couple of sea cucumber sightings including this unknown small one that the hunter seekers found.

I flipped a few rocks and also found yet another sea cucumber. This is probably the Purple under-a-stone sea cucumber.

Unfortunately, the rain over mainland has brought about lightning and thunder in the vicinity so we had to cut short the trip by 20 minutes and evacuate out of the reef.

While walking back near the sandy lagoon where the high shore is, we came across this Horn-eyed ghost crab (Ocypode cerathophthalmus) that was running real fast. It fascinated many of us!

Here's the second ghost crab that we encountered along the way back to the washup point.

Near the washup point, a few of us saw this really huge grasshopper.

Soon, it was time for sunset and also time to leave the island. This is probably the last time I will be guiding on this island as Juanhui (in TMSI) and her volunteers will take over from here.

Last but not least, my most grateful thanks to my group: Fiddler crabs! Everyone was enthusiastic and also patient in learning about the wonders of nature.

I especially find Elijah, the boy on the front row second from left, really inspiring. He is not scared of animals and insects, has an sphere of influence even at a young age (he brought two other friends beside him to this trip after his experience at Semakau), and has a great memory and love for nature. :-)

1 comment:

Ivan said...

That strange swimming crab looks like it could be Charybdis feriata.

Here's a pic for comparison:

And a similar crab was spotted at CJ in 2005 (scroll down to the bottom of the page):

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