Australia: Live sex show returns to Great Barrier Reef for repeat performance next month

Daniel Bateman, The Cairns Post 14 Nov 17;

Scientists nervously awaiting weather forecasts for Great Barrier Reef this summer, fearing bleaching
THE world’s greatest sex show is likely to return for a repeat performance next month.

Divers have been wowed by the annual coral spawning on the Great Barrier Reef, which was triggered over three nights last week, starting Wednesday.

Scientists believe, like previous years, this year’s mass reproductive event will be split over two months, with a second major spawning set to occur on the natural wonder in early December.

There has been concerns that consecutive mass coral bleaching may have dampened corals’ reproductive potential this year, however videographer and marine scientist Stuart Ireland, of Calypso Reef Imagery, said this did not appear to be the case last week.

“It was very similar to previous years,” he said.

“I was out at Moore Reef, and we probably saw about 10-20 per cent of the corals go off on the nights we were out there.

“So that’s a considerable amount, considering it’s going to be spread out over probably 6-8 nights with a split spawn, rather than concentrated down to 2-3 nights.

“It’s definitely substantial, and seeing that the corals that were under stress from bleaching, that’s quite amazing.”

During coral spawning, coral polyps produce millions of eggs and sperm, which they release simultaneously into the water.

The phenomenon usually occurs after a full moon, under specific conditions including day length, tide height and salinity levels.

Australian Institute of Marine Science researchers are in the process of surveying corals at various reef sites to determine whether the Reef’s overall reproductive output had been affected by bleaching.

AIMS researcher Dr Andrew Negri said the surveys, which involved close examination of coral polyps to see how many eggs were present, could take up to 12 months to complete.

“Logic would tell us that the overall reproduction of those northern sections (of the Reef) is very much going to be down on previous years,” he said.

He said the reports of large amounts of eggs in the water was a “glimmer of hope” that corals had been able to survive the two mass bleaching events.