Spawning coral could help rebuild parts of the Great Barrier Reef
AN INCREASE in coral spawning around Daydream Island could help restore the Great Barrier Reef over time.
The highly anticipated annual event began in November, about 3–5 days after the full moon.
Daydream Island marine biologist Johnny Gaskell has witnessed coral spawning on the fringing reefs around the island for the past five years.
He said the method of reproduction could help rebuild other parts of the reef, depending on the current.
“The importance of it here obviously is because some of the north-facing bays impacted by Cyclone Debbie are lacking the coral colour they had due to storm damage,” he told the Whitsunday Times.
“The great thing about this type of reproduction is that spawning can repopulate other areas in the region. So the spawning at Daydream Island could help repopulate some of the coral at Blue Pearl Bay, for example.
“It’s dependant on where the current carries it.”
Mr Gaskell said he saw more coral spawning around Daydream Island this time than there was last year, with the most significant day being November 27.
But after diving in about 80 sites around the Whitsunday islands, there were more positive signs, he said.“There is less coral at the sites we go to, due to Cyclone Debbie, but there are still quite a few good sites of both hard and soft coral,” Mr Gaskell said.
“We’ve seen some real positive signs the past couple of years.”
The coral spawning, which happens once a year, involves colonies and species of coral polyps simultaneously releasing their tiny egg and sperm bundles into the water.
The spawning occurs after a full moon and when rising water temperatures (usually 26 degrees or above) have stimulated the maturation of the gametes (eggs) inside the adult coral.
The day length, tide and salinity levels also appear to be factors in deciding when the event will take place.
However, even if the coral spawning does spread to other sites, it’s unlikely there will be a noticeable change any time soon.
Mr Gaskell said it could be months before polyps formed and much longer before they became visible to the human eye.
“It could take over a year before the species we’re likely to see from spawning can be easily recognisable,” he said.
“It’s different depending on the species of coral but you start to see more colonies after a few months.”
❝The great thing about this type of reproduction is spawning can repopulate other areas — Biologist Johnny Gaskell