Jul 28, 2007

Sea anemones of Sisters Island

The moon was full, if rather hazy and the crazy Sea Anemone Team were out once again. This time, we bring Dr Daphne, world expert on sea anemones, to Sisters Island.

I confessed to her that we rarely look at sea anemones at Sisters because it's just teeming with all kinds of other marine life. So it was a rather refreshing look at one of our favourite shores, with an Anemone-Only Hunt and a promise to ignore All Other Lifeforms.

Shortly we soon found lots of the frilly sea anemones (Phymanthus sp.) that Dr Daphne wanted to have a look at. Although they are VERY common on our shores, we know virtually nothing about them.

Dr Daphne wants to confirm whether those that look different are indeed different. One of the Phymanthus species is named after Singapore! Phymanthus singaporeansis. She says if she can't really find any difference, they might all be OUR Singapore Sea Anemone! Ron has more photos and stories about the hunt for frilly sea anemones on his tidechaser blog

And as we hunted for these rather well camouflaged and generally well embedded frilly sea anemones, we came across a lovely large Merten's carpet anemone (Stichodactyla mertensii).

How delightful! It was home to False clown anemonefishes (Amphiprion ocellaris)! There was one big mama fish and two small fishes. Those are not her babies, but unrelated anemonefishes that settled into the sea anemone. These fishes can change gender. The biggest fish is the female, and the next biggest the mature male. Should the female die, the male will change into a female and the next largest fish take his place as the mature male!

Dr Daphne checks the sea anemone carefully to be sure it isn't Stichodactyla gigantea (which we haven't been able to see yet in our trips). She confirms it is NOT S. gigantea. It is indeed Stichodactyla mertensii because it has those large colourful bumps on the underside of the anemone. (The next day, Dr Daphne tells me she thought further about this anemone and she thinks it IS Stichodactyla gigantea. Because the bumps were NOT that colourful, because the tentacles were moving (even the parts without the fishes), because the oral disk was wavy and not flattened out, and because it was found in coral rubble and not among living corals).
The mama clown anemonefish is quite tame and undisturbed by our explorations.

Dr Daphne was reassured to see these wonderful fishes. She was surprised that there were no anemonefishes on the large anemones at Chek Jawa. I shared that we thought they were not there because the water wasn't salty enough at Chek Jawa. She thinks not. She thinks they have all been removed in the past. She says it's hard for new ones to settle if there isn't a source of these fishes nearby. How sad.

She tells us that these fishes can live for 20-30-40 years. As a result, the anemones that shelter them must live for at least 100 years or more! So we leave fishes and anemone alone, as they should be.

Sadly, these fishes and anemones are taken from the wild for the aquarium trade. These usually soon die either enroute or in the tank, as it is difficult for artificial habitats to mimic what nature provides. Dr Daphne says this is particularly tragic because in an aquarium, the anemonefishes don't need sea anemones for protection.

The other sad thing that Dr Daphne highlighted, is that many aquarium keepers think sea anemones reproduce by dividing. They sometimes even purposely divide these large long-lived sea anemones. She stressed that in fact, MOST sea anemone DO NOT. Certainly the large sea anemones don't, and when so divided will soon die. Most sea anemones have sex and don't reproduce asexually.

We also seriously hunt for the "NOT the Condylactis" sea anemone, and Ron finds one! They attempt to have a closer look at it but alas, the equipment lets them down. More on the tidechaser blog (Ron: it's called a Yabby Pump).

Dr Daphne also spots lots of other marine life, including this beautiful flatworm, possibly Pseudobiceros sp.
As the tide started to come in, we headed to the high shore. Along the way, I just can't help but see the teeming non-anemone residents (although we were supposed to focus on the blobs).

The Sisters lagoon is teeming with the Blue-spotted fantail ray (Taeniura lymma). Not only are there many of them, but they are often also half hidden in the sand. It's important to really watch your step.
There were lots of strange fishes that I've rarely seen and haven't a clue what they are.
And this cute little filefish (Family Monacanthidae) with a very bristley area near the tail.
Sisters Island is also just crawling with octopuses. YC shot this one in action! As it foraged, it rapidly changed colours and patterns.
As the tide rushed back in, we thought that's it, no more nems. But then, we start spotting sea anemones on the sandy area!

Dr Daphne says this one is a Peachia sp, distinguished by the five bumps in the middle of the mouth and the 16 tentacles in a single row. I've also seen this on sandy areas in our Northern shores like Changi.
When the Anemone Team digs one up to take a closer look, they are amazed at just how long it is! On the left are what we see of the anemones. It's tough to find them as they're small and well, just blobs. But its no problem for Eagle-Eyed Chay Hoon and the rest of the team.

We also spot an odd blob.Which squirted water like a watering can, when we took a closer look at it. A behaviour similar to the one we found on Changi (see Kok Sheng's wonderful creations blog). And we weren't squeezing it or anything. Dr Daphne will have to take a look at it in the lab to identify it.

Meanwhile, Dr Daphne has found a blob which looks different from the other blobs we've found. All in all, a most exhilarating day of discoveries!

On Wednesday, Dr Daphne visited St. John's Island at high tide and she found FOUR new records of sea anemones! One of them was quite high on the shore where most people probably wouldn't look for anemones.

She also shared that from just the brief trips she's had so far, she can easily confirm 15 sea anemone species for Singapore! There are more that she needs to look at more closely before she can be sure what they are.

Wow! Aren't our shores just amazing?!

Tomorrow, another shore to show Dr Daphne, and more to learn from her about our sea anemones!

See also other blogs about this trip for other stuff I missed.
The tidechaser blog spider conch, synaptid sea cucumber, brittle star, moon crab.
The budak blog a much more eloquent account of the trip


Hai~Ren said...

It's amazing that there's still so much to discover about our marine biodiversity. Pity that not many people are aware or appreciative.

It's also a pity that collecting of anemonefishes still occurs, since I've read that captive breeding on a large scale has been going on for some time.

P.S. Would love to join the crew on some of these trips, though depending on my busy schedule of course. How do I keep myself in the loop?

ria said...

Yes isn't it just amazing!

There's much we still need to do to raise awareness. If we work at this, I'm sure ordinary people will realise they can appreciate a wild place without eating or taking home parts of it.

We'll be glad to have you with us on our trips! I'll put you on the beachfleas mailing list so you can get updates of our trips. Just email me? hello@wildsingapore.com