By Gloria Seow, Education Committee Chairperson
|Uncle Marcus giving us a Show-and-Tell of the intertidal marine life at Changi Beach.|
The early morning shower did nothing to deter the exploration of the intertidal marine life of Changi Beach, led by veteran tide chaser Uncle Marcus Ng. Determined NSS Kids and their care givers showed up in force on 7 June 2015, equipped with booties, wellies and rain gear. There was a palpable excitement as the ebbing tides exposed a wide swathe of inviting seagrass meadows.
The seagrass ecosystem supports a somewhat different marine cast compared to the coral rubble habitat prevalent on the rocky coastlines of Chek Jawa, Sentosa and Labrador Park. Growing from a sandy substrate, seagrass is the primary food of the Dugong, also known as the sea cow. Sometimes, Dugong feeding trails can be seen around Changi and Chek Jawa, formed as these massive mammals gobble up the seagrass, roots and all.
|We also spotted the icon of Chek Jawa – the Knobbly Sea Star.|
As we walked gingerly on the luscious green carpet, we found the brightly-coloured Pink Warty as well as Thorny Sea Cucumbers in good numbers. If one observes carefully, feathery feeding tentacles can extend from the mouths of both sea cucumber species, in search of organic particles and plankton. Someone spotted a Ball Sea Cucumber, a spherical softy that is usually buried in sand or hidden amongst seaweed. When threatened, this sea cucumber behaves like some others in its family – it ejects its guts out.
Uncle Marcus then pointed out the White Urchin. This spiky creature likes to doll itself up with bits of material such as seaweed and shell, which serve as camouflage or sun shield. After the urchin dies, its green test (ie. skeleton without spikes) can often be seen along the shoreline. We also came across the less common Thorny Sea Urchin, which has spines-growing-on-spines. These spines can move independently to transport the animal around, and are pretty fascinating to watch.
|Our trip highlight was a 5-cm Longspined Waspfish, sometimes mistaken for the infamous Stonefish.|
Next, we found a number of compact Biscuit Sea Stars as well as spindly-and-spiky Brittle Stars. Uncle Marcus was hopeful of us seeing the uncommon Knobbly Sea Star, the icon of Chek Jawa. As luck would have it, we came across a juvenile at the very end of our walk. The Knobbly uses its numerous tube feet on its underside to feed on micro-organisms, dead creatures, sponges, soft corals, clams, snails and other invertebrates. As echinoderms, these three sea star species are symmetrical along their five axes.
The highlight of our walk had to be the Longspined Waspfish, a well-camouflaged brown fish that can be mistaken for the infamous Stonefish. We found this 5-cm long cutie hiding inside a Fan Clam, of all places, and tipped it into a transparent container for a closer look. Due to its cryptic colouration, it is often overlooked even though it is supposed to be common on Singapore’s shores. Uncle Marcus showed us the row of venomous spines lining its dorsal area. These spines protect it from predators and are not used to catch prey.
|Some of our finds included (from clockwise) Thorny Sea Urchin, Biscuit Sea Star, Sea Hare, Sand Dollar and Ball Sea Cucumber, all released at the end of our walk.|
Other creatures spotted included the Sea Hare, Hammer Oyster, Sand Dollar, Striped Hermit Crab, various crabs, gobies, tube worms, etc. As the drizzle became more intense, we sought shelter under a big pavilion. Children and their parents took the opportunity to view and photograph some of our finds up close, as they were temporarily housed in a clear receptacle. Before bidding Changi Beach goodbye, we released these marine creatures back into their beautiful habitat.
|A Biscuit Sea Star on a bed of luscious seagrass.|