Cyclone Gretel’s gift for Great Barrier Reef

CYCLONE Gretel may moving well away from the Far North's coastline, but it appears she will be leaving the Great Barrier Reef a parting gift.

The Category 2 cyclone, which formed in the Coral Sea late Saturday night, was located about 460km northwest of Norfolk Island at 5am today, travelling southeast at 48km/hr.

The Bureau of Meteorology and the US National Oceanic and Atmospheric Association have reported that while sea temperatures are still above average for this time of the year for the Reef, they are likely to start to decrease throughout the rest of March and into April.

The Great Barrier Reef Marine Park Authority says the cyclone could help chill water temperatures, by creating unsettled weather across the Reef, to prevent a mass coral bleaching event.

 

Hard coral growing on the reef wall of Moore Reef, part of the Great Barrier Reef Marine Park, off the coast of Cairns. PICTURE: BRENDAN RADKE
Hard coral growing on the reef wall of Moore Reef, part of the Great Barrier Reef Marine Park, off the coast of Cairns. PICTURE: BRENDAN RADKE

GBRMPA, in its latest reef health report released late last week, states that sea surface temperatures have already started reducing across the marine park since March 8, at depths down to 30m in some areas.

While coral bleaching has been reported at several Far Northern reefs, including Moore Reef off Cairns, the authority's chief scientist, Dr David Wachenfeld, said the peak period for 2019-2020 bleaching was still expected to occur within the next week.

He said GBRMPA would start aerial surveys this week to scan the marine park for further signs of whitened corals.

The surveys will follow the past flight paths of surveys carried out during mass bleaching events on the Barrier Reef during the summers of 2016 and 2017, including the Torres Strait.

It is expected the flights will take about nine days, dependent on weather.

"It will the results of those surveys that will give us the really quantitative information about the extent of bleaching on the Great Barrier Reef," Dr Wachenfeld said.

During the mass coral bleaching events on the Great Barrier Reef in 2016 and 2017, most of the impact was observed in the Far North, with Lizard Island considered ground zero.