Apr 12, 2008

Chek Jawa with TeamSeagrass

Another dawn trip, this time with a large group of TeamSeagrass volunteers to monitor our fabulous seagrasses at Chek Jawa.As soon as we arrive, we quickly get sorted out, and say hello to the regulars at the Chek Jawa Info Kiosk such as Max the Dog.We quickly head out, some of us having discovered a new way to carry the transect square.While most of the rest headed for the usual transect sites, I went with Siti and Shufen and a few of the others to show them an enormous patch of Beccari's seagrass (Halophilia beccarii) that the Naked Hermit Crabs recently discovered as they were doing a net cleanup at Chek Jawa a few months ago. It was a good thing so many volunteers turned up today.

Beccari's seagrass is the smallest seagrass found on our shores (0.5cm long). It has a banded pattern compared to the plain green of the more common Spoon seagrass (Halophila ovalis); see the lower left photo of a small green H. ovalis next to regular sized H. beccarii.Beccari's seagrass has long oval-shaped leaves that emerge in a rosette of 5-10 tiny leaves on long thin stems; see top left photo. It is considered a rare and uncommon seagrass with a distribution restricted to the Bay of Bengal and South China Sea.

We were glad to find a large patch of this rare seagrass. Large enough to do a 50mx50m transect! Wow!
Soon, the team were hard at work setting up the site and doing the readings.In Singapore, Beccari's seagrss is more commonly found near mangroves, usually on hard (rather than soft) ground and rather higher up on the shore. We found more patches among the mangrove trees as well (this is the same situation at Sungei Buloh, the only other place in Singapore where we know this seagrass grows). So it's really special to be able to find a site to monitor its growth!

The new Beccari site overlooks the scenic Pulau Sekudu or Frog Island, which lies just off Chek Jawa.Soon we were done, and were off to look to set up another site for the Fern seagrass (Halophila spinulosa).

There's always time for a quick group photo.And to look at the shorebirds feeding at Pulau Sekudu.Elsewhere, the more common seagrass on Chek Jawa is Spoon seagrass (Halophila ovalis).Which can grow REALLY huge on Chek Jawa (also on Changi).
As we looked for Fern seagrass (Halophila spinulosa) and headed past the Chek Jawa boardwalk, we realise Fern seagrass grows right up to the rocky shore!Elsewhere, apparently, Fern seagrass is only found sub-tidally. That is, it is not exposed at low tide. Hmm...so much more to learn about our seagrasses.

Along the way, we discovered a few new things.

I noticed a row of Bubble shell snails (Family Haminoeidae) on the very soft silty mud. Although I've seen these snails before, this is the first time I've seen this sort of behaviour. Bubble snails indeed have a bubble-like shell that is thin and oval. The body of the snail can expand to be much larger than the shell. Some release a sticky purple secretion when disturbed. It has a well developed headshield, used to plough beneath the sand. It grazes on tiny algae growing on the surface of the mud.

Further along at the jetty legs, we came across a rather sad looking Flowery soft coral (Family Nephtheidae). A closer look revealed a pair of possibly Ovulid snails (Family Ovulidae) on the soft coral.Ovulid snails eat the soft corals they are found on. One of them looks like she was laying eggs! There were round white blobs among the soft coral. The white jelly-like stuff behind the snail has a similar pattern as the soft coral. Indeed, Ovulid snails are perfectly camouflaged in their host. Like the real cowrie, Ovulid snails cover their shells with a part of their body called the mantle. The ovulids usually have mantles that match their host in pattern, colour and sometimes even texture.

Today, the water was swarming with pretty jellyfish! Trailing long tentacles.There were small ones and big ones all bobbing around with the incoming tide.

On the boardwalk, I met this friendly group of visitorsWho for some strange reason, insisted on taking a photo of me. So I took a photo of them!

Alas, all may not be well for Chek Jawa.

On the shores near the new Beccari site, there were still lots of large abandoned driftnets. And some new nets as well among the mangroves, although the Naked Hermit Crabs removed a huge pile just a few months ago.

As we were leaving the Beccari site, we saw in the distance a man enter the shore (by bicycle) and then head out with a bucket, a plastic bag and a stick.Also rather disturbing, I encountered TWO Biscuit sea stars (Goniodiscaster scabra) that looked like they were unwell.Here's the underside of the first one. The tip of the arm looks more like it's disintegrating rather than having been chomped on by a predator.

Here's the upperside of the same sea star.
Nearby, I found another sea star with similar injuries.Oh dear. The last time sea stars disintegrated when there was massive flooding in Johor in early 2007, resulting in a drop in salinity at Chek Jawa. This badly affected some of the marinelife there, especially the sea stars and carpet anemones. And it has been raining quite a bit recently...

However, the carpet anemones seemed fine, so far.We need to continually monitor our shores so as to better understand and thus protect them.

Kok Sheng has compiled and analysed the separate observations of stressed marinelife during this trip. See his excellent cj project blog for more details.

Other blog entries about this trip

  • MORE amazing marine encounters on the nature scouter blog
  • Bubble snails, horseshoe crabs, more sea stars on the ramblings of a peculiar nature
  • All about the people, visitors, seagrassers and more on the teamseagrass blog
  • More sightings Beyond the Boardwalk on the budak blog
  • Anecdotal observations of stress at Chek Jawa recently: making sense of the recent observations of stressed sea stars, sea cucumbers and other marinelife at Chek Jawa recently on the cj project blog

No comments: