Friday, August 15, 2008

A starfish special

3 arms too many?
A Starfish special
Many thanks to Kok Sheng
NUS student and fellow labmate at computer terminal
Kok Sheng’s Blog. Highly Recommended!

Recently we visited St John's Island, to the south of mainland Singapore. It is not very well known among local teenagers. It is where you find the Tropical Marine Science Institute (TMSI) and lots of cats.



St John Island once held a prison for Singapore, or more delicately phrased by Singapore Tourism Board, it once was a penal settlement. It’s located relatively far from mainland Singapore, so the extent of damage from land reclamation works are lessened. We have our very own reef at St John! The Tropical Marine Science Institute is situated on St John, and has facilities to help researchers find out more about our local marine life. It is over here that the experiments are held for our starfish feature.



Starfishes are not fishes, no matter what their names suggest. They belong to phylum echinodermata, meaning that they are in the same family as sea cucumbers and sea urchins. They have pentaradial symmetry, having 5 lines of symmetry, although some starfishes have more than 5 arms. The do not walk with their 5 arms, but rather have hundreds of tube feet below their arms which move the entire starfish at once without bending the arms. They are most famous for their ability to regenerate lost arms.

Want to learn some more about starfishes?

Starfishes are extremely important to the reefs. The different species occupying the reef serve different functions:

The predators

The infamous starfish known as Crown of Thorns preys on corals. They invert out one of their stomachs, and happily digest away the helpless animals. While this sounds extremely brutal and cruel, and before you scream 'blue murder', it is important to have a small number of them on the reefs. They keep the fast growing corals from wiping out the slower growing ones. (although now their huge populations just seem to wipe out all the corals)

The cleaners

Starfishes like the Blue Sea Star eat dead stuff like crabs and fish, and also forage around the bottom of the sea floors for organic films. They are important for nutrient recycling in the ocean.

The population controls

Blue Sea Stars also eat sponges, which compete with corals for space, and also bore holes in the calcareous skeletons. The comb sea stars feed on clams, and the cushion star feeds on algae, controlling the populations of organisms which could usurp the reef.


To all those aspiring to keep starfishes as pets, they demand even greater care than your average cat and dog. They die if not given filtered salt water from the sea. They die if you not circulate the water around their tanks. They die if you leave too much food around and foul up the tank. And to top it off, they are literally spoon-fed (or forceps fed if they are small enough)



(The mouth is at the bottom of the starfish. To film this video, the starfish was turned upside down, thus the tendency to keep flipping over. Please do not overturn starfishes you find for entertainment, and don't feed them random objects)

Interesting, isn’t it?
Can you be responsible for feeding it everyday?
Don’t keep one in an aquarium.

(Photos by Jacque and Angie)

Jacque and Theophilus finished work at 4:02 PM

______________________________

the marine junkies
Jacque and Theophilus
18071990 / 28081990
NUS High School
NUS Marine Biology Labs

drop a line
reefmealone@gmail.com

thanks
Nudibranchs drawn by Prof. Chou
(hand drawn! wow!)
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