big sisters bleach watch

On Saturday morning, I embarked on my very first shore trip. This trip was organised by Ria, the woman behind Wild Singapore and one of the pioneers of the marine conservation movement in Singapore. Thanks to my friend Sam , I got in touch with Ria and signed myself up for the Sisters Island Bleach watch. One of the purposes behind this field trip was to document the extent of coral bleaching in the reefs around Singapore.

Coral bleaching is the whitening of corals, due to stress-induced expulsion or death of their symbiotic, zooxanthellae, or due to the loss of pigmentation within the protozoa. The corals that form the structure of the great reef ecosystems of tropical seas depend upon a symbiotic relationship with unicellular flagellate protozoa, called zooxanthellae, that are photosynthetic and live within their tissues. Zooxanthellae give coral its coloration, with the specific color depending on the particular clade. Under stress, corals may expel their zooxanthellae, which leads to a lighter or completely white appearance, hence the term "bleached".

Once bleaching begins, it tends to continue even without continuing stress. If the coral colony survives the stress period, zooxanthellae often require weeks to months to return to normal density. The new residents may be of a different species. Some species of zooxanthellae and corals are more resistant to stress than other species.

Bleaching occurs when the conditions necessary to sustain the coral's zooxanthellae cannot be maintained. In Singapore, coral bleaching could be caused by increased water temperatures, changes in water chemistry, oil pollution from ship collisions, and increased sedimentation due to land reclamation.

We assembled at the unearthly hour of 3am and departed from the Marina South Pier for Pulau Duah (Sisters Island in Malay). When we arrived, the tide had stretched all the way out (appeared to be less than 0.5m), leaving a stretch of sandy shore, coral rubble and rock pools to begin our discovery. Some of the creatures sighted include a blue spotted sting-ray, an octopus, various colourful crabs, a giant clam, seahorses and various types of fish. But the most compelling find for everyone, has to be a juvenile hawksbill turtle found snoozing away under some coral. Must have been my lucky day because some of the guys have been doing this for years but this is the first time they have seen a turtle. For me, the turtle and the spectacular sunrise made my virgin shore trip, a truly enriching and memorable experience that was probably worth every sandfly bite I got.

Next up, my virgin trip to an actual reef, and perhaps the largest and most diverse submerged reef in Singapore; Cyrene Reef