A sea turtle was seen in the sea next to the Marina Barrage on 10 Dec. Thanks to Calvin Ng for sharing this video. He explained that the sea turtle "was sighted on the short viewing platform parallel to the barrage which is just next to the carpark."
Meanwhile, lots of dugong feeding trails were seen at Chek Jawa during a survey on 14 Dec.
More about Singapore's sea turtles and dugongs on the wild fact sheets.
For more sightings of mega fauna in Singapore waters.