Giant clams, molluscs and gastropods joined the Great Barrier Reef’s headline event, the annual synchronised coral spawning, across much of the 2,600km (1,615-mile) length of the Reef, putting on a jaw-dropping show after some corals performed a curtain raiser in November.

This underwater snowstorm of coral sperm and eggs showcases one of the world’s most visually incredible natural phenomena.

Sunlover Reef Cruises Master Reef Guide Michelle Barry and Marine Education Leader Abbi Robinson monitored the event at Moore Reef alongside the Sunlover pontoon.

Barry, a marine biologist who has worked on the Great Barrier Reef for 15 years and witnessed eight spawning events, said being underwater last night was absolute chaos in the best possible way.

“At one point I completely lost visibility — there were so many eggs and sperm in the water it felt like being caught in a pink underwater blizzard as trillions of tiny coral larvae form and drift, every creature on the Reef gets involved. A real reminder that the Great Barrier Reef is very much alive.”

Sunlover’s female-led marine biology team conducts weekly biodiversity surveys and long-term monitoring across sites surrounding Moore Reef as part of the Federal Government’s Tourism Reef Protection Initiative.

This data is invaluable to understand the health of the Reef. Further south, Lady Elliot Island’s Environmental Manager and Master Reef Guide Jessica Blackmore said the Southern Great Barrier Reef was in great shape heading into the summer reproductive season.

The mass coral spawning is triggered by the November full moon, but different coral species follow slightly different biological clocks.

Triggered by water temperature and the lunar cycle, coral spawning is a mass synchronised event where entire colonies of corals release their eggs and sperm bundles simultaneously.

Anyone with clients wishing to visit during the spawning in 2026, it typically occurs one to six nights after the October, November and December full moons.