Great Barrier Reef bursts into life during annual coral spawning

MOORE REEF, GREAT BARRIER REEF, QUEENSLAND, AUSTRALIA (FILMED OVER TWO NIGHTS) – The Great Barrier Reef showcased its annual spawning last week, with underwater footage captured on November 8 and 9 showing the moment future generations of coral reef are created.

Coral spawning takes place when colonies and species of coral simultaneously release trillions of egg and sperm cells for external fertilisation. Mass spawning normally occurs only once a year, in the spring and after a full moon, turning vast swathes of the ocean red with a slick of the cells.

The Great Barrier Reef, a UNESCO World Heritage Site, stretches 2,300 km (1,430 miles) along Australia’s northeast coast and is the world’s largest living ecosystem. It consists of almost 3,000 individual reefs, including Moore Reef where Australian videographer Stuart Ireland recorded the spawning over two nights. The event typically lasts several nights and this year it is widely expected to be a split-spawn, with another event expected in early December.

Gareth Phillips, a marine biologist and owner of education centre Reef Teach in Cairns, said monitoring this year’s spawning was particularly important after recent coral extreme events destroyed at least 35 percent of the northern and central Great Barrier Reef last year.

“Coral spawning increases distribution of the corals to different areas and increases genetic resilience. This initial spawn saw high numbers of gametes released which is very positive,” he said.

Warm seas around the reef killed some two-thirds of a 700 kilometer (496.4 miles) stretch of coral last year after warm water caused the coral to expel living algae, triggering it to calcify and turn white, a process known as bleaching. That was the worst die-off of coral ever recorded at the reef.

The reef, a popular tourist site worth billions of dollars annually to the Australian economy, is threatened by dredging, sedimentation and disease. Global issues such as ocean acidification and warming due to climate change also affect the reef’s health.

Heralded as one of the seven natural wonders of the world, the Great Barrier Reef is home to 400 types of coral, 240 species of birds and 1,500 species of fish. It is worth about $5 billion (3.8 billion USD) in tourism each year.