06 July 2016

Checking up on Pulau Sekudu

We arrive well before dawn for our annual survey of Pulau Sekudu aka Frog island, just off Changi and Pulau Ubin.
There is indeed a rock in the shape of a frog on the island!
Fortunately, we didn't see mass coral bleaching. We saw some signs of a recovery in sponge diversity, the seagrasses are doing well, and lots of interesting marine life.


I saw six small colonies of Boulder pore coral and none of them were bleaching. I didn't see any other kinds of hard corals.
There are some clusters of Zebra coral and most of them look alright.
I came across a few small colonies of Flowery soft corals and they were all bleaching.
There were also many small Ball flowery soft corals. They seemed alright.
The usual sea pens are still on the shore and I didn't see any that were bleaching: several Spiky sea pens, many Flowery sea pens and for the first time, I saw many Sea pencils here. I saw only a few Cerianthids and they seemed alright.
I only saw a few small sea fans. Like this Candelabra sea fan, most were a bit 'chewed up'. We saw more and larger healthier sea fans during our survey in Jul 2015.
The most abundant cnidarian on the shore were Haddon's carpet anemones. They came in all kinds of colours. I did not see any that were bleaching. Other anemones seen included Swimming anemones and Big hermit hitching anemones.
Pulau Sekudu is among the few places so far where I've seen green Posy anemones next to the usual maroon ones. Are they the same? I only saw one that looked a little bleachy.
Our Nothern shores have a great variety of echinoderms. I saw two large Knobbly sea stars and one baby one. The rest of the team saw more. There are also many Common sea stars here as well as Plain and Painted sand stars. Biscuit sea stars small and large remain the most common sea star seen today.
Kok Sheng found this feather star.
Chay Hoon found this Oval heart urchin above the ground. I get worried when this happens as healthy heart urchins are usually well buried. There were also some (but not a lot) of sea cucumbers.
One Diadema sea urchin is still there.
I was delighted to see a greater variety of sponges growing on the rubble. This is similar to what we saw at Chek Jawa a few days ago. The most common sponge remained the Melted chocolate sponge. During our last survey in Jul 2015, most of the rubble at Pulau Sekudu had just a sprinkling of sponges or none at all. Most of the rock was covered by a variety of seaweeds. I hope this means the sponges are coming back after a noticeable reduction in Aug 2013.
Many animals live on sponges like these purple Synaptid sea cucumbers.
Scuttling among the sponges is the Marine spider, which is a true spider that lives on the intertidal. At high tide, it waits in a bubble of air, coming out at low tide to forage.
There are lots of crabs on the shore. Among the special ones I saw was a Mosaic crab, a Maroon stone crab, one Common hairy crab that we more often seen in the South, and of course, many Swimming crabs of all kinds.
I was glad to see several small Reef octopuses. I didn't see any slugs but the rest of the team saw some.
I saw this Fine-lined flatworm that was swimming upside down.
The shores are lushly covered in seagrasses, mostly Spoon seagrass (both small and large leaf blades). These are home to a wide variety of animals. Including many many Fan shell clams, also many large White sea urchins.  The lagoon and reefy arm around it is no longer very bare and sandy as we saw in Jul 2015. Sprinkles of seagrasses, seaweeds and other marine life are now seen here.
I came across two clumps of Tape seagrass with very long leaf blades one with female flowers, small patches of Fern seagrass, and some Needle seagrass.
Is this a dugong feeding trail?
The patch of Serrated ribbon seagrass is still there. The ground where they are growing is very soft, a similar observation made during our survey in Jul 2015.
A look at the serrations at the tips of this seagrass.
At sunrise, we can see Chek Jawa near the Chek Jawa beacon. Later on, Kok Sheng pointed out that there was a group of wild boar near the beacon. And it appears, I accidentally photographed them too.
We were treated to a spectacular purple sunrise. I wonder if this is caused by pollution?
While we did not come across any nets, I came across a fish trap. It had one filefish that was dead.
The rest of the team also came across fish traps, some having many fishes in them. Here's the two traps and fishes caught in them that Jonathan Tan saw.
In total, we found 7 fish traps. During our last annual survey in July 2015, we also found 8 fish traps. It's a pity more is not being done to manage the fishing impact on Pulau Sekudu and Chek Jawa.


This little island lies just off Chek Jawa on Pulau Ubin. It is part of the Chek Jawa Wetlands that is managed by NParks.
Pulau Sekudu is off limits since 2007 and requires special permission from NParks. Thanks to NParks for permission and support to do these predawn low spring tide surveys of Chek Jawa. Thanks also to Chay Hoon for making all the transport arrangements. And the team for helping to cover as much ground as we can during the narrow low tide window. Thank you!

Chek Jawa and Pulau Sekudu may be affected by the 2030 landuse plan by the Ministry of National Development. The plan includes plans for a road link (black line) from the mainland jumping off at Punggol, crossing to Pulau Ubin through Chek Jawa to jump off to Pulau Tekong before circling back to the mainland on Changi East. Proposed reclamation (in yellow) will bury Pasir Ris shores, Pulau Sekudu and Chek Jawa as well as a large amount of shore at Changi Beach.

Click on images for larger view.
I feel it is thus important to update our understanding of what is going on in the field at these sites including Chek Jawa and Pulau Sekudu.

We probably won't be back to visit Chek Jawa and Pulau Sekudu until next year. I hope these unique and beautiful shores remain well until then.

Posts by others on this trip


Others on this trip: Juria Toramae, Nicholas Yap, Ivan Kwan, Heng Pei Yan

MORE shore explorations today

Meanwhile, the rest of the usual team were out exploring other shores. Here's posts of what they saw:

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