We saw 10 of these large colourful Knobbly sea stars! They are indeed the highlight a trip to the shores of natural Pulau Semakau.
snapping shrimps! We also learned to spot the many Hairy crabs that wander the shore like little teddybears.
Common sea stars in 'mating' position. Sea stars of the genus Archaster have a unique mating behaviour. The male, which is usually smaller, seeks out a female during the breeding season. He then moves on top of her, his arms alternating with hers. Their reproductive organs do not actually meet. Sperm is merely released by the male when the female releases her eggs, for external fertilisation. This behaviour is believed to increase the chances of external fertilisation. So much so that the males do not need to be large and are thus usually smaller than the females.
Heart urchin which is related to sea stars -- you can see the 'star' on its skeleton! Heart urchins usually live burrowed into the sand, so we seldom see a living one above ground.
Garlic bread sea cucumber and several Durian sea cucumbers.
yellow ribbon of eggs, probably laid by a nudibranch or snail.
Cauliflower nudibranch! I don't come across it very often.
egg capsules of some kind of squid, laid among the green sponge-seaweed.
Upside down jellyfish! The jellyfish harbours microscopic, single-celled algae (called zooxanthellae) inside its body. The algae undergo photosynthesis to produce food from sunlight. The food produced is shared with the jellyfish, which in return provides the algae with shelter and minerals. It is the algae which gives the jellyfish its colours. This is why the animal prefers to be 'upside down', with its bell facing the sea floor and oral arms facing upwards toward the light. When one is turned the 'right' way up, it will slowly turn itself upside down again.
Giant carpet anemone. But no shrimps or clown anemonefish.
What is coral bleaching and why this is of concern on the Bleach Watch Singapore blog. I saw a few hard corals that were pale or yellow. These included very yellow or whitish Disk corals, a pale Pebble coral and some pale Small Goniopora corals.
Anemone corals and all of them seemed alright.
Cauliflower corals I saw were pale at the tips. All the Sandpaper corals I saw were mostly still dark brown. The Torch anchor corals were a little pale. The Brain corals I saw were alright.
Asparagus flowery soft corals that were oddly coloured, but most of the Leathery soft corals I saw were alright.
Haddon's carpet anemone that was bleaching. It did not have shrimps in it.
|TeamSeagrass monitoring in 2010.|
Oh dear! The seagrasses have almost disappeared!
|Photo at the crossing path by Loh Kok Sheng in 2010.|
Kok Sheng was a regular guide at the Semakau walks.
an intertidal walk at Pulau Semakau on the NEA website.
Pulau Semakau is NOT the same as the Semakau Landfill. The Landfill was created by destroying all of Pulau Saking, and about half of the original Pulau Semakau by building a very long seawall. Fortunately, the landfill was constructed and is managed in such a way that the original mangroves, seagrass meadows and reefs on Pulau Semakau were allowed to remain. The eastern shore of Pulau Semakau is right next to the seawall of the Semakau Landfill, opposite the petrochemical plants on Pulau Bukom.
Phase 2 of the Landfill was just recently launched. This involved closing the gap of the seawall on the Semakau Landfill, forming one big pool where incinerated ash will be dumped. NEA worked to limit the damage to natural shores during the construction work for this expansion of the landfill.
On the drive from the NEA Jetty to the start point of the walk, we pass by Terumbu Semakau (a submerged reef) and the Eastern shore of Pulau Semakau. Although I no longer guide at Pulau Semakau, we regularly survey Pulau Semakau and the terumbus around it, by landing amphibiously in a dinghy.
Subaraj Rajathurai for inviting us to guide at this walk! It was quite nostalgic to guide at Pulau Semakau so many years after starting the guiding system there in 2005 with the Raffles Museum now called the Lee Kong Chian Natural History Museum which still conducts these walks. I also remember it was Keith Hillier who got NEA to include me when it was decided to open the Landfill and Pulau Semakau for recreational activities. Keith sadly has passed away and I miss him so much.
Other work I've done at Semakau include organising the first survey of Semakau's mangroves led by Zeehan Jaafar and Loh Tse-Lynn. As well as setting up TeamSeagrass who monitor seagrasses at Semakau as well as Chek Jawa and Cyrene Reef. Also helping Marcus Ng who wrote the awesome books about Semakau's amazing marine life published by NEA.