Saturday, July 25, 2009

Lively East Coast Shore

During my previous post, I shared about the rich sea fan gardens that can be found at the seawalls. As East Coast is a reclaimed shore, seawalls were constructed to prevent erosion of the reclaimed sand along the shore. Bays are thus formed between walls and over time, marine life have colonized the sandy shore.

The special find of the day on the sandy shore by Agnes must be this Spiny sea star (Gymnanthenea laevis).

This species of sea star is usually found amongst seagrasses and sometimes at the coral rubble. Thus, I was surprised that Agnes had found this star not only on sandy shores but also at a reclaimed shore.

An interesting feature about this sea star species is the presence of spiny bumps, sometimes with very lage flat plate-like spines. The underside is pale usually without any patterns.

Some parts of the sandy shores are scattered with some rocks. The Thorny sea cucumber (Colochirus quadrangularis) is sometimes seen among the rocks.

Once in a while, one may find creatures living on creatures like this brittlestar on the Thorny sea cucumber. James last found Eulimid parasitic snails on these cucumbers on our previous trip.

Black rubbishy looking structures can also be encountered and these are not thrashes but the tubes of tubeworms. Somehow, they trap all sorts of shells, leaves etc among the bed of tubes. If you stare at these tubes on the shore, you can see the worms coming in and out of the tube.

This moon snail is called the Lined moon snail (Natica lineata) as it has pretty brown lines on its shell. They have a huge body called the mantle that can engulf prey such as smaller snails like button snails.

Talking about snail, Yong Jian found this uncommon Frog snail (Bufonaria sp.) that has a long muscular foot. At the end of the foot is a thin and flexible operculum. The operculum serves as a trapdoor against predators and stress when the foot retreats into the shell.

When snails die, their shells are not left to rot or decompose. They are made into good use by becoming homes for the hermit crabs like this Striped hermit crab (Clibanarius sp.). Therefore, do not collect shells from seashores as you are depriving hermit crabs of their home.

As you can see, hermit crabs use all sorts of shells as their home. When they grow bigger, shell exchanging takes place just like how Singaporeans upgrade into a bigger flat or home. But for the crabs, it is purely out of necessity.

Other than hermit crabs that are confined in the comforts of their shells, there are also crabs that freely crawl about like this tiny swimming crab.

But the most special crab find must be this handsome Sally-light-foot crab (Grapsus albolineatus).

This crab has very long walking legs tipped with pointy claws. With these legs, the crab clings tightly so it doesn't get washed away in the waves, and can scramble quickly among slippery rocks.

In addition, this crab is a scavenger and it eats seaweeds. It has relatively small pincers that work like scissors to snip and scrape off edible tibits.

As we have enjoyed the photos earlier, the sea fan garden area among seawalls and rocks are just too beautiful to behold.

But it is also important to remember that they are also not-so-colourful creatures on the rocks, like the hydroids that can sting you badly if you touch them.

Encrusting on rocks are also large patches of the Zebra coral (Oulastrea crispata) with greenish tinge within each animal or polyp.

It's amazing rich marine life has returned even to a reclaimed shore. We have seen certain stretches of East Coast being badly affect by sedimentation or unknown reasons and also by dredging. Some spots are destroyed before they are discovered.

Thus, it is important to document all the remaining stretches so that we as Singaporeans can be aware of our very own natural heritage and be proud of its existence, even on a reclaimed shore. So long as we do not pollute, litter or destroy the shore, life will continue to exist, building up an marine ecosystem right at our very own shorelines.


Unknown said...

The tiny swimming crab is it a baby flower crab ?

Unknown said...

Not too sure, but it is possible :)

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