Island reefs on the mend
A LOCAL coral ecologist says reefs around Magnetic Island are recovering after recent coral bleaching events.
Dr Andy Lewis, director of the Coral Sea Foundation, said the reef in Nelly Bay has almost completely recovered, with few bleached corals, and Geoffrey Bay was well into recovery despite still having about one-third of the corals showing pale colouration.
Dr Lewis has lived on Magnetic Island for 20 years and has seen a dramatic reduction in coral bleaching in Nelly Bay over the past six weeks.
“In Nelly Bay it has gone from 70 per cent of corals showing bleaching, to less than 5 per cent”, he said.
“In Geoffrey Bay there are still about 30 per cent of the corals bleached, but most are well into recovery of their symbiotic algae.
“It’s a similar story in the wider local area north into Halifax Bay.”
Dr Lewis said recent aerial surveys of the Marine Park showed bleaching was widespread on inshore fringing reefs, and the outer shelf reefs from just south of Cairns to just south of Townsville.
He said that sweltering, clear-sky weather through the latter stages of January and into February caused ocean temperatures to rise into the range above 30C.
“By mid-february coral bleaching was being reported at numerous locations in the Coral Sea and along the Great Barrier Reef, including in the waters of Magnetic Island just off the coast from Townsville,” Dr Lewis said.
“In the case of the current bleaching event, the good news is that clouds and wind arrived in late February and ocean temperatures dropped back below the bleaching thresholds fairly quickly by early March.
“In my backyard around Magnetic Island there are still many pale corals, however at this point there is minimal mortality and many corals either didn’t bleach or have begun to regain their algae and their colour, which gives me hope that most will recover.”
He said the fact the systems had survived and recovered from these storms and previous bleaching disturbances show questions still needed to be answered when it comes to coral bleaching and the survivability of different corals.
“We should not be decrying the loss of the Great Barrier Reef while this reef system is battered and bruised but still very much alive and doing its best to recover,” Dr Lewis said.
“The threats to the reef system from climate change-driven bleaching are only going to increase in frequency, so it is essential we understand how the reef is coping with these more frequent disturbances in order to manage it effectively.”