We were discussing yesterday if the cushion star that we saw at Semakau is the same one. The cushion star was first spotted on 20 January 2007, subsequently on 17 March and again on 18 March.
I'm glad I have my camera with me everytime I see this big and beautiful cushion star. After examine and compare all the photos, saw a scar at the same spot on all the 3 photos. If this is true, that means we've been seeing the same cushion star.
I'm glad to know that this cushion star is the resident there as we saw her almost at the same corner for the last 3 sightings. On the other hand, why only the same one was spotted, is this the last one on Semakau? Are there more that we didn't encounter yet?.... I'll see if I can find another cushion star this Saturday.
Perhaps, the so called "scar" is unique to all cushion star? Anyone got more info about cushion star?
Perhaps, the so called "scar" is unique to all cushion star? Anyone got more info about cushion star?
Wow! That's an excellent observation and analysis.
ReplyDeleteFor the Common sea stars (the kind that stack one on top of another) each sea star has a white spot or 'scar' on the upperside, slightly off centre.
This is the madreporite, a sieve-like plate through which the sea star sucks in sea water. The sea water inflates the sea star's body. And hydraulic pressure of the sea water helps the sea star move its body parts (like its tube feet).
The 'scar' you saw on the cushion stars might be the madreporite.
I'll go check my books and have a closer look at my photos!
Wow, thanks for that observation and making us take a closer look at the stars!
Remember reading some where that divers often spotted cushion stars on the reef slopes of Semakau.
ReplyDeleteI can still remember during the boat ride to Semakau, on the day which you spotted our first cushion star, I was still telling Luan Keng that I was sure one day we would see one, since the divers had been spotting them!
The cushion stars probably stay on the reef slope most of the time since they are coral feeders, and there are probably more corals on the slope.
But possibly one fine day, another one will creep up the reef slope to the intertidal area :)