Stars of Singapore

Sea stars are encountered on almost every shore in Singapore. Even the most "beat up" shore will have some kind of sea star. Unlikely starry shores include this one in the photo above, of Cyrene Reef which lies in the middle of Pulau Bukom, Jurong Island and faces our container terminals! While Chek Jawa appears to have the richest variety of sea stars, there are also sea stars that are only found on our Southern reefs.

Here's a quick look at some of Singapore's Stars!

Although often called starfish, these creatures are not fish at all! So we prefer to call them sea stars. Sea stars belong to a group of animals called Echinoderms (Phylum Echinodermata).

Here are some sea stars that can be found on our sandy shores.
The sand stars (Astropecten spp.) have large spines on the sides of their narrow arms and can move about speedily across the sand on their pointed tube feet. They also burrow rapidly into the sand. They come in a variety of patterns.

The Common sea star (Archaster typicus) is alas, no longer common. Those on Chek Jawa were wiped out in early 2007 following the massive floods in Johor. But there are signs of them returning. They are still commonly seen on Southern islands such as Pulau Semakau, Pulau Hantu and Kusu Island. Often you might seen one Common sea star on top of another, with arms locked. This is a unique mating position of this kind of sea star. Their reproductive parts don't actually meet. They are just getting close to one another getting ready to release eggs and sperm at the same time.

On the rocky shores and seagrass meadows, more sea stars!The small Crown sea star (Asterina coronata) is usually brown and drab and found under stones on our Northern shores. But sometimes, bright orange ones can be seen! Gymnanthenea laevis is a rarely seen star, sometimes with orange spots at the tips of its arms. It is most often seen among seagrasses. Big ones can pinch your fingers if you hold it, as they have large pinching structures.

The Biscuit sea star (Goniodiscaster scaber) really looks like it was made with a cookie cutter! This neat star is often seen among seagrasses as well as on coral rubble areas in the North.

These sea stars are rarely seen and may be seasonal: the large eight-armed Luidia maculata and the small, rather boring looking Nepanthia sp. They are sometimes seen on undisturbed shores in the North.

Sea stars of the coral rubble and reefs include some of the largest of our stars, some of which can be bigger than your face!
The Cake sea star (Anthenea aspera) with short fat arms is sometimes seen and comes in a wide variety of colours and patterns. The big red Knobbly sea star (Protoreaster nodosus) is the highlight of any trip to the reef. Besides red ones, you might also see brown or even white ones. They are seen both at Chek Jawa and Pulau Semakau, in coral rubble areas.

The Cushion star (Culcita novaeguinea) doesn't look like a star at first glance, but a look at the underside shows its sea star feature of five grooves. This cuddly star is seen in deeper waters in reefs, more often by divers than visitors to the intertidal.

The business side of the sea star is underneath!
The mouth is in the centre of the arms, and there are grooves on the underside of each arm. These grooves contain rows of tube feet. Sea stars use their tube feet to move around. Sea stars also use their tube feet to manipulate food. Some sea stars also breathe through their tube feet!

Sea stars use seawater instead of blood to pump up their bodies and move their tube feet. Thus it is stressful for sea stars to be left out of water for too long. Please return sea stars quickly to where you found them.

What do sea stars eat? Some sea stars placidly gather edible bits from the water or surface. But most sea stars are scavengers or carnivores, 'sniffing' out their meal by the chemicals released by the prey or dead animals. Among the more common prey are snails, bivalves, crustaceans, worms and other echinoderms. Some sea stars specialise in a certain prey. Some sea stars feed on sponges, sea anemones and corals. A population explosion of the notorious Crown-of-Thorns sea star (Acanthaster planci) can decimate reefs. Fortunately, this sea star has not been encountered on our shores.

More FAQs about sea stars

I went to the seashore and didn't see any sea stars! Sea stars tend to be more active after dark. In fact, we notice that as night falls, the stars literally come out! In the sand as well as in the sky. Some stars are very secretive, hiding under stones or in crevices among coral rubble. Even big stars like the Cake sea star can be stuffed deep under coral rubble.

I heard sea stars can regenerate from broken limbs. Can I try and see what happens if I chop one up?
Most sea stars can regenerate portions of limbs that got nibbled off by a predator. But this regeneration takes a long time. You can't see it happening in front of your eyes. And meanwhile, the sea star is handicapped by a lost limb. Very few can reproduce from broken limbs, and none of our sea stars do that. If our sea star is severely injured, it will die. So please don't mutilate the sea stars. It is cruel to do so.

Should I take home the dead sea star I found on the shore?
All the sea stars that you see on our shores are probably alive. You are unlikely to come across a skeleton of a sea star. Dead sea stars disintegrate quickly and do not leave behind whole skeletons. A live sea star also has moving tube feet. When removed from the water, however, sea stars will retract their tube feet and may appear dead.

Should I take a sea star from the shore and put it in my home aquarium? Aquarists and scientists don't really know what the various sea stars eat. So your sea star might die of starvation. Or it might start to eat its tank-mates. For this reason, sea stars are not popular for the home aquarium.

Threats to sea stars: Sea stars are not eaten by people. They are also not that popular for the live aquarium trade as they tend to eat their tank-mates. However, in some places, sea stars are harvested alive and dried to be sold as cheap ornaments. This is a cruel waste! Don't support this harmful trade. Don't buy souvenirs or trinkets made from marinelife.

Our sea stars are no longer as common as they used to be. Common sea stars once littered the Changi shores, but they have not returned since the reclamation. The big red Knobbly sea star used to be considered one of the most common sea stars in the Malay peninsula. Now both the Common sea star and the Knobbly sea star are listed among the threatened animals of Singapore, due to habitat loss.

Stay tuned for more sea star cousins
More about brittle stars, feather stars, sea urchins, sea cucumbers and other echinoderms of Singapore.

Links to more about sea stars
Lane, David J.W. and Didier Vandenspiegel. 2003. A Guide to Sea Stars and Other Echinoderms of Singapore. Singapore Science Centre. 187pp.
Photos of sea stars of Singapore on wildsingapore flickr
Sea stars and echinoderms at Changi recent sightings on the tidechaser blog

1 comment:

tHE tiDE cHAsER said...

Thought I'll just add that some people do eat starfish :P

I've seen people eating fried sea stars on the streets of China.

Sea stars are also believed to be an aphrodisiac, and have been
consumed not only by the Chinese, but by the ancient Romans as well.
Have also seen packaged dried sea stars sold as ingredients of 壮阳汤 (aphrodisiac soup) when I was in China.

For more info, just google for "fried starfish" or "starfish aphrodisiac".