Nature lovers have cried foul over an incident involving a boat that appeared to have struck a barely submerged coral reef last month off Pulau Hantu, one of Singapore's Southern Islands.
On Nov 9, project officer Toh Chay Hoon, 37, spotted a dive boat called MV Nautica resting on the reefs at Terumbu Hantu, off Pulau Hantu.
The photos Ms Toh took show a yacht beached on what looked like a hard surface, with the vessel's brown bottom exposed.
When contacted, the Maritime and Port Authority of Singapore (MPA) said it is investigating the case. Its spokesman told The Straits Times that vessel owners can be fined up to $5,000 if they are found to have contravened regulations by navigating in a reckless or negligent manner, or in any way dangerous or likely to cause human injury or damage to property.
The company that owns the boat has since apologised and said the vessel has not been used since for diving trips in the area.
Mr Ricky Koh, managing director of MV Nautica Diving, the boat's owner, said the incident was caused by a storm. He said the combination of currents and winds had dislodged the anchor and pushed the vessel aground.
This was despite the care taken by the captain to anchor the boat "a safe distance from the reef", he said.
"Due to the falling tide, the captain made the decision not to attempt any more movement and to wait for the next high tide to move the boat out."
Mr Koh added that this option was considered the best, as it would not cause additional damage to the boat and the reef.
Environmentalist Ria Tan wrote about the incident on the local wildlife website she runs. She also highlighted five other instances where large holes and gouges have been spotted in other reefs around Singapore since 2010.
These were believed to have been caused by boats striking reefs, she said.
Dr Intan Suci Nurhati, a coral researcher from the Singapore- MIT Alliance for Research and Technology, said cases of boats striking reefs can be identified by the physical damage.
"Such damage is different from coral bleaching, where the corals turn white but their skeletons are still intact on the reefs," she said.
Boat grounding incidents have a profound effect on the marine ecosystem, said experts.
National University of Singapore marine biologist Zeehan Jaafar said: "When a boat hits the reef, its bottom scrapes a portion of the reef off the seabed."
Organisms that are immobile or not able to move away quickly enough, such as corals, anemones, snails and small crustaceans, will perish.
Damage to the affected area can be long-lasting, she added. "Organisms like corals grow only a few centimetres a year, and it will take many years before the area is colonised by other organisms and return to the way it was prior to collision."
Mr Koh said his firm regretted the incident. "We were deeply hurt by this incident and by the potential damage it would have caused to the precious Pulau Hantu coral reef... We offer our sincerest apologies to any individual or community offended and impacted by this incident."