Jul 5, 2007

Sekudu: Life slowly returns

Another dawn trip, this time to Pulau Sekudu which lies just off Chek Jawa.
As always, whenever we are on the Northern shores, we do a 'health check' to see how they are doing following the mass deaths earlier in the year. Kok Sheng is doing a study of recovery on Chek Jawa and hopefully some of our observations will be useful to him as well.

The carpet anemones are doing very well at Pulau Sekudu. With many large specimens.And in the usual colour spectrum including purple and green!
There were also some other sea anemones. The one on the left is a swimming anemone. It is seasonally abundant and sometimes we see lots of them.
The one on the right used to be seen in the hundreds, literally carpeting the sand and rubble. Today, there were some, but not a lot.

The peacock anemones, however, were abundant.
As their common name suggests, they come in a wide range of colours.
Among the animals that died in numbers on Chek Jawa were sea stars, sea cucumbers and other Echinoderm relatives. It was thus very heartening to encounter a Cake sea star (Anthanea aspera).This one wasn't as large as we have seen them in the past, it was about 10cm across with arms. Those seen in the past could reach 15cm. But it was quite healthy and happy.

We also came across a brittle star scuttling for cover as the sun rose. These animals used to be plentiful on Chek Jawa and Pulau Sekudu, but are usually out and about only at night.
Kok Sheng had previously noted mats of tiny mussels on Chek Jawa. We saw some too on Pulau Sekudu today, forming mats of about 30cm wide. These mats were seen at the base of large boulders and even on top of the boulder as well (where they would be submerged at high tide of course).
These tiny mussels (Musculista sp.) have thin shells (left) and produce threads that trap sediments and form a mat that binds them together.
On one mat that was growing on a boulder (right), I noticed tiny baby green mussels (Perna viridis) starting to grow. Wow. We must check on this when we next visit.

What was most exciting, however, was to see sponges starting to grow on the rubble and rocks.
There were very few sponges seen, but these were relatively large (about 5-8cm).Even the tiny yellow one (right) was exciting to see. Why? Because nudibranchs and flatworms feed on sponges and we love to see these colourful animals. Although none of these animals were seen today, perhaps they will soon return.

There were also lots of egrets and herons 'fishing' in the lagoon today.

Pulau Sekudu lies next to a major shipping lane used by commercial vessels as well as military ones. This large grey vessel slipped by, our team oblivious to it.
This beautiful and fragile island has always been subject to much harvesting.

Today, we saw at least two boats coming by to place and to set fish traps all around the island. After visiting Pulau Sekudu, one of the boats headed over to Chek Jawa, and then to the mangroves at Pulau Ubin.
Some of these fish traps have been abandoned (left). Some of us saw copperbanded butterflyfishes in one of these traps. I saw a dead filefish with eyes popping out floating by. It probably recently died when it was exposed out of water trapped in either a fish trap or a drift net. Drift nets are also commonly encountered on the island.

Hopefully, marine life on Pulau Sekudu can withstand these pressures.

Being just opposite Chek Jawa, what happens on Pulau Sekudu is likely to affect Chek Jawa. Pulau Sekudu was less impacted by the flooding than Chek Jawa and will be an important source of new life on Chek Jawa.


koksheng said...

Glad you all saw the cake seastar. It seems this one is different from the one I saw that was bigger at about 20cm. Seems that there may be more :)

ria said...

Wow! 20cm! Actually, that's more like the way they used to be.

Yes, it's a good sign. Hope you have a fruitful day out tomorrow!

Hai~Ren said...

Oh well. One person's marine refuge is another person's fishing ground.

Am I correct in saying that unlike other neighbouring countries, Singapore does not have anything remotely like a Marine Protected Area? (besides Labrador, which I believe falls under the National parks Act) Do Chek Jawa, Sungei Buloh, and other coastal/marine habitats receive any form of legal protection, or are they really available for anyone to openly fish and collect?


beachbum said...

Hello Ivan,

Singapore does have it's fair share of protection laws. Rather than focus on the offences specifically (ignorance of the law is no excuse anyway), 'fishing and collection' activities create a negative impact on the ecosystems and the marine flora and fauna. Singapore has already cleared most of it's natural coastal habitats and has lost a lot of it's rich marine biodiversity. Most collected species either die off during the transfer process, soon after collection or have vastly shortened lives and are prevented from contributing their reproductive genes to the ecosystem. The marine aquarium industry does pose an incredible impact on natural ecosystems but this fact is not mentioned by the industry. What you see in the shops is only a small percentage of the survivors. Think about this. There are better ways to appreciate nature.

The places you mentioned do have enforcement by various authorities such as AVA, NParks, MPA and Sentosa Dev Corp (Southern Islands). So it's best for collectors not to try. Fishing may or may not be permitted in certain areas. Subsistence fishing is slowly phasing itself out.

Thank you for highlighting this issue. Together we can help safeguard appreciating nature 'in the wild' instead of in glass containers or museums.