Jul 6, 2008

A happy day on Changi

6am and it's a super low tide on Changi! The early morning sandy shore was crawling with tiny hermit crabs and tiny little sand stars (Astropecten sp.).The hermit crabs obviously didn't quite like the sand stars. Sand stars are carnivorous and generally eat mainly snails and clams. But these sand stars are known to be unfussy about what they eat.Every now and then, a little hermit crab would nip at the tips of the sea star's arms. Then quickly run away!Like elsewhere, some of these sand stars had tiny little white snails on their arms. These are probably parasitic snails. Must be awful not being able to pick them off your arms.Another burrowing snail sometimes seen on Changi is this Olive snail (Family Olividae). This particular one seem to have survived a ferocious attack on its thick smooth shell. By a crab?The underside of the snail was still alright, and the animal itself seemed ok.

The seagrass meadows today seemed a little thin. There was also not much seaweed. There were plenty of large white sea urchins (Salmacis sp.) as well as many skeletons of these sea urchins. So perhaps the 'urchin season' is nearly at an end. There were also quite a lot of sand dollars (Arachnoides placenta).

There were many large carpet anemones but none I saw with anemone shrimps, not even tiny ones. Except for this one.Here's the big fat mama anemoneshrimp (Preclimines brevicarpalis).And the smaller, more transparent papa shrimp.

We also saw a large glass anemone and the hermit crabs had little anemones on their shells. But not many other kinds of sea anemones. In fact, there were also very few peacock anemones and sea pens. This is rather odd as this shore is usually teaming with these animals.

Kok Sheng had asked us to check on the situation with the Button snails (Umbonium vestiarum). And we found a patch of these tiny little snails!I've often been annoyed that these snails tend to float up when we try to take a closer look at them. Makes it difficult to photograph them. Siti mentioned that in some snails, the first chamber is used in flotation. We also noticed that the floating snails tended to stick together, forming 'rafts'.

Dr Dan remarked earlier that this is an important behavioural aspect. This may allow these snails to disperse to new areas quickly. Indeed, as I thought about it some more, it may also be a way for them to escape from predators. If they are dug up while submerged, they float straight up away from the ground thus escaping nasty predatory snails and other animals that can't swim.As we observed the raft of snails, one by one, the snails would sink and quickly burrow back into the sand. The snails have tiny little eyes on stalks, and a long leaf-like foot. Amazing!

A first-time encounter for me was this strange black fan worm with white spots on its feathery tentacles.And what a marvellous surprise! Chay Hoon finds a feather star! A first time for me on Changi.Today we also came across the strange green sea star that was first mentioned in the manta blog in April and again in May. The big white patch is an injury to the sea star.Here's a closer look at the upper side. The big 'knobs' are made up of tiny bumps. Something had taken a nibble off the top of this poor sea star.And a look at the underside. It has pale pink tube feet with suckers at the tips. We have no idea what kind of sea star this is!

Besides the sand stars, we didn't see any other kind of sea stars on this shore. But there were lots of thorny sea cucumbers (Colochirus quadrangularis), buried ball sea cucumbers (Phyllophorus sp.) and smooth sea cucumbers, some warty sea cucumbers (Cercodemas anceps), one transparent sea cucumber (Paracaudina australis) and the strange beige sea cucumber that looks like sand.

The edible animals seemed particularly scarce today: no Sandfish sea cucumbers (Holothuria scabra), few Gong-gong (Strombus canius), few Fan shells (Pinna sp.), no horseshoe crabs.

There were lots of people out on the shore especially after sunrise.
Some were just looking around.
Some had plastic bags collecting stuff. I couldn't get to see what as they avoided me, but Siti saw someone with some Fan shells. I also came across piles of large Window-pane shells (Placuna sp.) that looked like someone collected them and then changed their minds. In the distance a man with a changkul digging for worms, probably for fishing.There was much fishing going on at the shore. We had to step over many lines strung out on the shore in the morning. And the team gathered some abandoned lines on the shore. There was also a group of fishermen on an inflatable boat off shore. Later in the morning, one went out into the incoming tide with a cast net.

There was also a big group camping on the shore, probably because tomorrow is a school holiday.Thus it was very heartening to come across one guy walking out onto the tidal flats to RETURN these two amazing snails! We asked if we could take photos of them and he let us have them.On the left, a large and living Bailer snail (Melo melo) and on the right, a lovely Noble volute (Cymbiola nobilis). Both these snails are listed among the threatened animals of Singapore due to habitat loss and over-collection.

From Ng, P. K. L. & Y. C. Wee, 1994. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. The Bailer snail is "thought to have been exterminated from our waters, but a recent isolated sighting confirms their continued presence". While the Noble volute is "confined to the region, particularly Singapore and southern Peninsular Malaysia, presently uncommon on our reefs although abundant in the past".

The Bailer snail was very much alive, although it seemed a little slow. The Noble volute was perfectly fine. Our last encounter with someone collecting a Bailer snail had a less happy ending.After checking on the snails, Samson and HB took them far out into the water to release them. Hopefully, they will be safe from collectors.

What a wonderful way to end a great day out on Changi!

More about this trip and the Melo melo on the manta blog.


Ivan said...

Good to see more bailer snails. And hurray for people returning them to the sea!

Anonymous said...

I doubt they are threatened as the book says, but probably common in deeper waters. Drift nets snag them very frequently. Likewise, noble volutes are very common. It's about time someone revises the 'book' that we are so fond of drawing reference from.

Ria Tan said...

Before making comments about the hard work put into writing a book and drawing up a list, would you want to find out more about the issues?

I've outlined some of the issues in this post

Commander said...

I agree with Ria. Biodiversity is dynamic and changes very often. In the field of butterflies which I study, a couple of reference books refer to some species as "very rare" whereas in the field today, these species are considered common garden species! Hence the status may also change depending on the evolutionary progress that each species follows.

FYI, NParks is now coordinating a 2007/2008 version of the Singapore Red Data book and I was told that it's in its final stages of vetting before going to print. Hopefully, the various taxonomic group experts have updated the status of the species that may have changed over the past 14 years since the last Red Data book was published.

Anonymous said...

Many listed species in the red list were obselete on the first day it was published! Didn't you people know about it? If you are ignorant then simply refer back to those authors who wrote it.

Unfortunately they will never tell you at what speed it was compiled and from what kind of sources.

Follow whatever book you wish but never 100% if you are smart enough.

By the way, all these nature blogs are more like hypes than the actual situations. Don't assume everyone reading it will believe what you wrote and your agendas (hidden or open).

Anonymous said...

Junked that red data book the moment I received (bough it off the web)!! It reflected badly on the kind of standards you have if any! Shame shame!

Joe Lai said...

Heehee, true! How very true! Should we call it Red-faced OutDatedBook? But then, we must respect the 'doyens' of Singapore lah. They have PhDs, you know. : ) They must know everything what! Plus... they can get info from dedicated outdoor people like Ria also.

Ivan said...

Funny how almost every time bailer snails get mentioned in this blog, the potential for coherent and constructive discussion seems to plummet.

While I cannot judge whether some of the other comments are an accurate assessment of the Singapore Red Data Book, at the very least, it represents the best attempt we've had so far in documenting the status of our imperiled wildlife. It might be obsolete and outdated, but given the difficulties and challenges of trying to study wildlife in Singapore, I think we should look upon it as a yardstick, to see how we can more accurately survey our wildlife.

The book certainly shouldn't be taken as gospel truth, but neither do I think such condemnation is entirely justified.

Anonymous said...

I am Ismail and a kaki from fishingkaki.com told me I was featured here. I am surprised. From all the links I visited it looked like these blogs are like environment pressure groups.

First of all it is not nice to take photos of the public and put it up on the net. Are we committing a crime there?

Secondly it is rude to claim a person is old even under darkness. Remember how Donald of former US secretary of state was told off when he said "old and new Europe"?

I am 68 years old (relatively old in comparison). Changi used to be a quiet place before the reclamation for the airport. Fishing is the most common pass time and traps, nets and lines were used. Shellfishes were collected as food especially pen shells, gong gong, and the 2 big shells photographed here. There were many large cockle shells (blood cockle or something like this) and all of these are seasonal.

I hope these blogs are not trying to ban fishing on our own home ground.

Ria Tan said...

Welcome Ismail to the blog and thanks for leaving a comment.

It's good to hear from others who love our shores. And from someone such as yourself who knows our shores well.

I do know of the fishingkaki forum and have worked with some of your members such as SFAS. I greatly admire the efforts of SFAS and members of the forum in promoting responsible fishing on our shores.

The long list of activities at Changi that day shows that many people still appreciate our shores.

I do believe all of us who love our shores must feel something for wanting to keep things sustainable. So that our children and theirs can continue to enjoy these simple pleasures.

I get a strong sense that you also feel this way.

I personally feel this is possible if we treat our shores responsibly, only take what we need and use what we take.

Like any other shore activity, fishing in itself can have limited impact if there is respect for reproductive fishes, consideration for numbers and species taken, an understanding of how non-target marinelife is part of the food chain, and the activity does not result in abandoned nets, lines and litter.

And if we give back to our shores. In terms of sharing information, raising awareness of issues and working with one another.

It is in this spirit that this blog is run.

It's heartening that some of the issues raised has resulted in discussion. I for one am always ready to learn from others who have a more intimate understanding of our shores.

I look forward to hearing more constructive views about the shores that we all love.

I didn't mention anyone's age. And I'm not so young myself and will soon see 50.

Let's continue to share about our shores. And work together so that everyone can continue to enjoy the shores for generations to come.

Anonymous said...

Ivan, Ismail and Ria are right. I apologize for my comment. Sorry.

Anonymous said...

You have nice photographs (I have kept some for personal use) and a noble cause but the normal folks there also have their rights to the beach be they uncles, aunties, boys, girls, fishermen and whoever, red list or not.

Keep those info flowing and thanks for your prompt updates. I will look forward to more finds.

Ria Tan said...

I'm glad the photos are of some use to you yy.

Please do use them. I've posted them to share that our shores are very much alive.

Some are on this blog as well as well as another 3,000 or so on http://www.flickr.com/photos/wildsingapore/

The flickr photos are sized to fit powerpoints, free for download, so please do use them to give presentations or share with others about our shores.

My hope is that with greater awareness will come fuller appreciation of our shores.

And more mindful exercise our right to, and responsibilities for, our shores.

I have learnt much from the comments left on the blog. Thanks to everyone who commented.

I hope there can continue to be further fruitful exchanges of views.

Anonymous said...

Noble cause? What a joke! Tell it to fishing folks across the Straits of Johor and they will laugh until jaws dropped! We have tons of bailers here!