Semakau at high tide

The Semakau Book Team were hard at work the whole of Saturday. While the dive team were busy underwater, a small intrepid team spent 8 hours out on the island at high tide.

With us were Chay Hoon and Ivan, and JC Chua and Yan Fei who work with Dr Jean Yong on our mangroves. Sean and James of NEA gave us a ride out to the shore (many thanks!) and also gamefully came along to have a look at the mangroves at Semakau.It was a very windy say, which made taking photos of the plants a real challenge. But it helped to keep the mosquitos at bay! And presented a real dilemna. We had to choose between taken mediocre photos or finding secluded areas to take good ones while donating blood.

It was a very long trip with lots of sightings so I've split this up into three posts. Here's some of the animals we saw and about our very long trip.
We had a very brief look at the mangroves while the tides were at minimum. There were algae covered mounds like soft carpets covered with little snails and dotted with young mangrove trees taking root.Among the many snails we saw were lots of Belitong (Terebralia sulcata) which have a distinctive shell opening (see the hole in the shell of the snail at the top left). There was also large Mangrove murex (Chicoreus capucinus) and lots of tiny Red berry snails (Sphaerassiminea miniata). We saw a lot of shells of Belongkeng (Family Ellobiidae), but no living snails. Wandering on the incoming tide was a lone Crown sea star (Asterina coronata), while lots of mudskippers of all kinds bounded just out of reach. Ivan also spotted many Land hermit crabs (Coenobita sp.)!

Some other animals seen included several dragonflies including this one.The Sea hibiscus bushes (Hibiscus tiliaceus) had some Cotton stainer bugs (Dysdercus decussatus) but not in such profuse numbers as we usually see at mangroves such as Chek Jawa. Another insect that was plentiful was some kind of white scale insect that infested several large mangrove trees. More about those in this following post.
There were also butterflies in the mangroves as well as in the forested area of Pulau Semakau. And I saw several in the grassy areas as well. It will be a job for the butterfly specialists to document these beautiful but very difficult to photograph animals!

Chay Hoon finds this strange thing on a leaf of Ximenia americana.Possibly a butterfly caterpillar? We didn't even know which end was the front of this little creature.
Among the sheltered areas, the mangrove leaves were festooned with the webs of tent spiders.The white spider on the left occupied the web in the photo above. There were other webs with bits of rubbish suspended in the centre which had other kinds of little spiders. I'm looking forward to visiting with the spider experts to check out the spiders of Semakau for the Semakau Book.

Of course, Semakau is full of birds. We could hear the twitter of all kinds of mangrove birds, the calls of Kingfishers and in the windy skies, many raptors overhead.On the shore, we spent some time watching this group of egrets fishing with the incoming tide. There was one black one in the group but he seemed very much at home with the rest. Birds will certainly be a big feature of the Semakau Book.

On the way out in the morning, we had to stop for a monitor lizard crossing the road, and there were lots of monitor lizard tracks on the shores. Ivan said he caught glimpses of geckos or lizards too. Hopefully the vertebrate experts will help us find out more about the non-bird vertebrates on this island.
In the midst of our little walk, we had to hurry back to shelter as a huge storm headed in. We spent some time feeding yet more mosquitos and a quick lunch (where JC Chua and Yan Wei invented the 'bee hoon wrap' as they ate it without chopsticks). As the weather cleared, we headed out for more exploring.By that time, the tide was so high that we had to trek into the forested areas as some parts of the shores were already innundated. What a novel experience for us low tide explorers. While some parts of the forested areas were thickly vegetated, there were others that were more open and full of ferns.

We must have walked the entire length of Semakau twice and some portions four times! And we sure saw a lot of plants (more about those in this post) and some sad situations (in this post). And after all that walking on the shore, it was time to walk some more, back to the NEA jetty. I was joking that after wearing wet booties for 8 hours, our toes might fall off and remain in our booties as we take them off. Fortunately, all our toes were intact, although rather wrinkled. But we sure had weary feet.On the walk back were the vast grasslands on the landfill which we had intended to look at today but just didn't have the time or energy to do so.In the distance among the waving grasses is the beacon that marked the old boundary of Pulau Semakau showing the portion of the original island that was reclaimed to form the landfill.

The grasslands and trees took root on their own, they were not planted. So exploring this area will be interesting.There were lots of beautiful wildflowers growing by the road side, and some were really growing very enthusiastically, spilling out to the road.It was a long long walk. And when we reached the jetty, we found the divers had decided to dive right at the jetty!Here's Eric and his lovely assistant. While his friend shows us what a black tip reef shark looks like, with his fins.. ha ha!They sure were a happy and energetic team, even after one full day of diving. Here they are making a non-standard landing at the NEA jetty so that the boat could pick us all up at one go. Eric said they saw a 1-metre tall sea fan on their dive and other marvellous creatures including possibly a new record of a pipehorse. We can't wait to see his photos.

On the way home, Eric the comsumate photographer points out the dramatic weather building up over us.The looming weather also made a rather gloomy photo of the reclamation works at Pasir Panjang Container Terminal, with Bukom's industrial installations in the background.But it was a great day out, exploring a beautiful shore that will need our love and attention to preserve. Here's more about some of the issues affecting Pulau Semakau and what you can do about it.

The Semakau Book is a project by the National Environment Agency (NEA) to showcase the Semakau Landfill as well as the biodiversity of Pulau Semakau and is scheduled to be published in 2009 in celebration of the Semakau Landfill's 10th anniversary.

More about Pulau Semakau on the wildsingapore website.

Some plants of Semakau

The rare Seashore Bat Lily (Tacca leontopetaloides) was one of the key objectives of this trip.This plant was first discovered by Joseph Lai during the Semakau mangrove survey conducted by Zeehan Jaafar and Loh Tse Lynn in 2005. This plant is listed as Critically Endangered in the 2008 Red List of threatened plants of Singapore.

This means there are fewer than 50 mature individuals, or more than 50 mature individuals but less than 250 with some evidence of decline or fragmentation. According to the Singapore Red Data book, in Singapore, it is restricted to a few populations in Pulau Semakau and Pulau Pawai (just opposite Pulau Semakau). It is rare here because of the loss of its preferred habitat, i.e., dappled shaded areas immediately behind sandy beaches. Fortunately, some plants propagated from Singapore stock have been planted at Bukit Batok Park.JC Chua and Yan Wei are very excited by the find. And James spots some flowering. We are very careful not to stomp on any seedlings as we take the photos.

The mangrove experts were also taking photos of common mangrove trees and plants. Most of these are well represented on Pulau Semakau, with quite a lot of trees of Rhizophora stylosa which is not as commonly encountered in our other mangroves and is listed as Vulnerable on the 2008 Red List. Alas, we couldn't find the Avicennia marina which was recorded during the 2005 Semakau survey, or any of the special mangrove trees that JC Chua had been sharing about finding on Pulau Pawai.But we did see several of the 'Pong pong' trees (Cerebera sp.). We're not sure if these are the special C. manghas as the flowers had a light yellow centre, and not a pink one. C. manghas is listed as Critically Endangered in the Red List of threatened plants of Singapore.It was nice to see a large bush of the Portia tree (Thespesia populnea). It resembles the more abundant Sea hibiscus (Hibiscus tiliceaus) with very similarly shaped leaves and flowers.Here is Thespesia populnea on the left and Hibiscus tiliaceaus on the right. Here's more on how to tell these two plants apart on the Mangroves of Singapore online guide.

We spent a lot of time on the the plants on the high shores as the tide was very high! Pulau Semakau has magnificent stands of the Seashore pandan (Pandanus odoratissimus) and lots of Ximenia americana which has oval fruits. Chay Hoon found a funny caterpillar on a leaf of one of these plants.

But we saw lots of plants that we have no idea about. An odd climbing plant.This climber with large leaves, and pretty purple flowers.A delicate plant dotted with little star-shaped flowers and bell shaped fruits.Several large bushes of this plant with a constellation of pretty white flowers.
This strange plant with hairy pods.A tree that looks like Sea almond (of which there were a lot) but with a different kind of fruit.And a tree with bright yellow flowers.

Pulau Semakau used to be inhabited by a kampung. So there might be some surviving ornamental bushes or trees that might have grown wild.

There sure is a lot to find out, especially for botanically-challenged shore explorers more used to looking at intertidal flora and fauna!

How is Semakau doing? And what you can do

Marine debris is a problem on all our shores. And Pulau Semakau is no exception. In our long exploration we discovered a stretch of shore that had accumulated a large amount of debris that had floated in.There was a patch on Semakau full of planks. Which had to be negotiated carefully as these often have vicious rusty nails poking out to impale careless feet.

This litter did NOT come from the landfill. The landfill is well managed and only incinerated waste and construction waste is buried there and properly done so that nothing escapes into the sea. A great deal of garbage floats in the sea, improperly disposed on land or from ships all over the world.

As is usually found on many of our shores, there were accumulations of plastic and styrofoam debris.

Marine litter can kill.
Styrofoam breaks down into little particles that eventually may enter the food chain and into our seafood.Similarly with plastic bags. And tragically, these often resemble jellyfish or other floating animals that are mistakenly eaten by marine life such as sea turtles. These may kill such marine life.
Abandoned nets and ropes entangle and drown marine life too. Recent sad examples of death by litter include a whale in Australia, a whale in Pahang and a dugong in Phuket. More media articles about marine litter on the wildsingapore news blog.

A bewildering array of trash had floated in.A tea kettle.A life vest.A cluster of mattresses. A very sad example of a 'sea bed'.
A refrigerator.A motorcycle helmet and large plastic containers.Even a large plastic safety barrier.The high spring tide had even brought large litter into the forested area, while winds probably brought more smaller bits in.

The International Coastal Cleanup Singapore effort collects data about the trash that lands up on our shores. Here is their latest data for 2008 on their blog.

In the most badly littered areas, we found mangrove trees that were obviously sick.One very large Sonneratia tree was infested with white insects, probably scale insects.Here's a closer look at the insects on another mangrove tree in the area.One Rhizophora tree had oddly patterned leaves. JC Chua said it probably meant some sort of mineral deficiency.Another Rhizophora tree had a pink propagule! The propagule is the long green seedling that grows on the mother tree. A pink propagule shows that all is not well with the tree. Chay Hoon has more details about this on her blog.

Elsewhere on Semakau, a large oil rig is parked just off the shore.This area off Semakau is designated for parking oil rigs for maintenance and repairs. Here's the public notice about the latest oil rig to be parked there.Pulau Bukom's industrial installations are also just off Pulau Semakau.These extensive installations lie just off the mangroves of Pulau Semakau.Our Southern islands lie next to major shipping lanes where huge ships ply in large numbers. Here's a container ship passing Pulau Jong which is just next to the Semakau Landfill.

This is why it is important to scientifically monitor the health of our shores. These include efforts such as TeamSeagrass that scientifically monitors our seagrasses as an indicator of shore health, and International Coastal Cleanup Singapore that collects data on marine litter. These efforts are part of global monitoring with methods that are standardised, tested and audited and generate valid data for assessing the health of our shores and guiding management and policy decisions.

These efforts rely on volunteers, so each one of us can make a difference simply by participating in these programmes.