Jul 19, 2007

Hantu: anemone or not?

The Sea Anemone Team and wildfilms were back out on the shore early this morning. This time we go to Pulau Hantu for a look at sea anemones in a reef habitat.

As soon as we arrive, we start hunting for those tentacly blobs that we've come to know better over the past few days.

Dr Daphne is particularly keen to find Edwardsia hantuensis that was described from a specimen from Pulau Hantu and thus named after Hantu. It's a tiny blob like thing similar to what Yuchen found yesterday at Chek Jawa.

Yuchen as usual, is the most enthusiastic and is really having a close look at the shore for this elusive little anemone.
We also learn along the way, what is NOT a true sea anemone.

Compared to the habitats at Changi and Chek Jawa that we visited the last two days, there are more anemone look-alikes in a reef habitat. To confound the first time anemone-hunter.

True sea anemones belong to Order Actiniaria.

This is sometimes called the Anemone coral (Goniopora sp.). It is a hard coral (Order Scelerectinia) with a hard skeleton. The polyps that make up this colony have long bodies with little tentacles at the tips. The skeleton is often hidden when the polyps are extended. This is a leathery soft coral (Order Alcyonacea), also a colony of tiny polyps with long bodies and little tentacles at the tips. They are embedded in a shared leathery tissue instead of a hard skeleton.
These blobs are corallimorphs (Order Corallimorphoria) and are NOT true anemones, although they do look very much like them.These are colonial anemones (Order Zoantharia). These clusters of little animals with long bodies and short tentacles may be connected to one another through underground 'roots'.Earlier on, during our Changi visits, we also learn that Peacock or Tube anemones (Order Ceriantharia) are also NOT true sea anemones.

So what are true anemones?!

This frilly looking animal is a true anemone called Phymanthus sp.
There's two of them in the photo above. They come in a wide range of colours and patterns and Dr Daphne is quite interested in finding out more about them.

Here's some of the variations I've seen in the past, from old photos. We saw some of these variations on Pulau Hantu today.Dr Daphne is quite keen to study the ones we saw on Pulau Hantu. It appears, although these sea anemones are VERY common, they have yet to be studied thoroughly!

These sea anemones are firmly embedded in coral rubble so they are very hard to get a closer look at. Fortunately, with the help of the indefatigable Trixie and Ivy, Dr Daphne manages to get a few. Swee Hee lends a manly hand with some of the more difficult situations.

Dr Daphne is also VERY interested in this little star-like anemone with very few arms.
These anemones are very shy and disappear instantly at the slightest trace of danger. I rarely see them. So we were lucky that Marcus, Liana and Yuchen were with us to help find FOUR today!

Here is some of the variations I've seen in the past.I used to call them Condylactis sp. but Dr Daphne thinks they might be something else altogether. I can't wait to find out more about them from her!

On our Northern shores (Changi, Chek Jawa), the common large carpet anemones are Stichodactyla haddoni. On our Southern shores such as Hantu, Stichodactyla mertensii is more common.
These humungous animals are easily identified by their brightly coloured undersides with pink or red spots, and long skinny tentacles arranged in rows. So there's no need to take a closer look at these sea anemones in the lab.Often, a pair of anemone shrimps may live in these large sea anemones. Anemone fishes are also commonly seen in these sea anemones, but we didn't see any today.

We also looked closely at seagrasses to try to find more of the teeny sea anemones that settle on the leaves. The few suspicious clumps I could see with my feeble eyes turned out to just be other blobs.

Dr Daphne earlier told me that these seagrass sea anemones actually hitch a ride on jellyfishes. When the jellyfish wanders over seagrasses, the sea anemones drop off and settle on the seagrass. While travelling, these sea anemones settle on and eat the jellyfish's gonads! (Gonads are a big word for reproductive organs). Life on the shores never ceases to amaze me!

Alas, although we combed the soft shore a second time on the way back to the boat, we failed to find the Edwardsia hantuensis.

Throughout the trip, dark clouds gathered and rolled towards the mainland. Here hovering over the petrochemical plants on Pulau Bukom, just metres off from the reefs where we were.On the opposite side of this ominous landscape, the sky was bright and blue!
But still, in the distance, dredging of some sort is going on near the reefs.
Our reefs on Hantu are rich with marine life that are interesting even to world renown scientists.

Let's hope developments around the island spare this amazing natural and national treasure of ours.

More stories and photos about the Sea Anemone Team on the budak blog

Anemone Workshop, 21 Jul 07
Dr Daphne later gave a workshop about sea anemones in general and the sea anemones we saw in particular. Here's some blogs about the workshop...
wonderful creations blog by Kok Sheng
habitatnews blog by Siva


JC said...

wonder if those "star-anemone" found on the rocks are Aiptasia, commonly known as Glass Anemone.

ria said...

Hopefully, we'll soon find out when Dr Daphne has a closer look at them!

One thing for sure, talking to her makes me realise a lot of what we think we know can be quite wrong :-)

The study of sea anemones is very complex and even among the experts there are differences of opinion as to identification.

Also, there is apparently currently major revisions underway in many Cnidarian orders including zoanthids and corallimorphs.

So things will probably continue to change.