Article: Frances Lam, aquarist at S.E.A. Aquarium
Photos: Hian Hian, Kenneth Chin and Colin Oei, curatorial team at S.E.A. Aquarium
S.E.A. Aquarium just celebrated our nation’s 51st birthday. As you know, there are five stars on the Singapore flag which represent the five ideals of democracy, peace, progress, justice and equality.
Here, we present to you five sea stars found at the aquarium which in some ways represent these five ideals:
Democracy – Crown of Thorns
Scientific name: Acanthaster planci
Animal family: Acanthasteridae
Natural diet: corals
Natural habitat: subtropical latitude of Pacific and Indian Oceans
Like a feisty freedom fighter, the Crown of Thorns is one sea star not to be trifled with. They are notorious for their venomous spines which pose a threat to careless divers, swimmers and corals alike. The venom contains asterosaponins, also known as saponins, which is released into the victim’s body when an unwary person or creature gets pricked by it. The effect will cause an unbearable pain that lasts for several hours, constant bleeding, nausea as well as swelling.
Crown of Thorns are carnivorous and wait for their prey in between coral colonies. They can climb in between sections of the coral colony using their tube feet and flexible body thus camouflaging itself. They then feast on corals by secreting digestive enzymes to absorb the nutrients from the coral tissue which will further lead to rapid deteriorating of coral skeleton and lastly, algae growth. So much so that they are capable of decimating entire coral reefs in very short periods of time.
Peace – Pincushion Sea Star
Scientific name: Culcita novaeguineae
Animal family: Oreasteridae
Natural diet: algae, diatoms, small detritus particles to clams and oysters, sea urchins, sponge tissue, crab larvae and other small organisms.
Natural habitat: Pacific and Atlantic Oceans, ranging from upper-Canada to Central America.
Pincushion Sea Stars are much gentler by nature as compared to other sea stars. They are mostly omnivorous and may occasionally feed on coral. These “peace loving” sea stars have a round pentagonal shape with a bumpy texture which resembles a thick pillow or cushion. Amazingly, they are also home to other marine animal in a very strange symbiotic way. Their body cavities contain water which allows small fishes to live inside them. In return, these fishes help the sea star clean its exterior.
Progress – Feather Star / Comatulids
Scientific name: Crinoidea
Animal family: Echinoderm
Natural diet: Plaktonic food
Natural habitat: Western side of the Pacific Ocean and on both sides of the Atlantic Ocean
Also known as Sea Lilies, these graceful little creatures possess feather-like appendages covered by numerous branches called pinnules. A closer look at the pinnules will reveal smaller translucent branches also known as podia, which are covered with sticky mucus used to capture any food that floats pass and transport the food down to their mouth.
At the central underside of a crinoid are a series of short tentacles called “cirri” which give them the flexibility to walk, swim or even grasp objects to move, or progress, from one point to another with ease.
Justice – Basket Star
Animal families: Asteronychidae, Asteroschematidae, Gorgonocephalidae, Euryalidae,
Natural diet: small mollusks and crustaceans
Natural habitat : Wide range of habitats around the world, from cold to warm waters. Most live deep under the sea, but some smaller ones also dwell in shallow tide pools.
Basket Stars are considered an echinoderm, distant relatives of sea stars and sea urchins. It is interesting to note that this particular sea star belongs to the Ophiuroidea class. Ophiuroidea comes from the Greek words ophis for snake and oura which means tail – words that presumably refer to the animal’s snake-like arms.
Basket Stars have 5 slender branches of highly mobile arms which does justice to its incredible flexibility. They wrap their flexible arms around their prey and transport it to the central body where the mouth is located. When threatened, this nimble creature will curl up into a ball when feeling as a protection mechanism.
Instead of blood, Basket Stars have a water vascular system that enables them to breathe and transport food and waste. This system is also connected to their numerous tube feet to facilitate locomotion.
Did you know?
The life span of a Basket Star is about 35 years and it can weigh up to 5 kilograms.
Equality – Red Knobbed Sea Star
Scientific name: Protoreaster linckii
Animal family: Oreasteridae
Natural diet: corals, sponges, invertebrates, worms and other sea stars
Natural habitat: Indian Ocean, usually around Indonesia, the Maldives and Africa
The spectacular physical attribute of the Red Knobbed Sea Star lies on its dorsal side. These red knobs are connected to each other by red strings which gives this sea star a grid-like appearance. On the underside, are thousands of tube feet which act like suction cups for the sea star to stick itself anywhere or move as it please throughout the ocean.
Each arm of a red knobbed sea star has a photoreceptor eye spot that allows it to differentiate between night and day or detect any kind of movement through the current. Predator or prey, it can see them equally well.
We need to feed sea stars one by one. They are such slow feeders that sometimes their food gets snatched away by other fishes in the habitat.
– Colin Oei, aquarist who takes care of sea stars at S.E.A. Aquarium
If you are a fan of sea stars, you can see all these and more at the S.E.A. Aquarium. Don’t forget to drop by the touch pool where you can view them up-close and have a feel of what they are really like!