Reef’s big night’s a star
TRIPS to the Great Barrier Reef to witness the night spawning of the coral are increasingly popular.
Michael Healy, Quicksilver group director sales and marketing, said: ‘‘We are finding the interest is increasing each year for our coral spawning night tours and our trips this year were fully booked over the three nights. Our luxury dive and snorkel catamaran Silverswift travelled to Flynn Reef where certified divers enjoyed two fully guided night dives. We also offered a guided snorkel tour for experienced snorkellers.’’
The ocean temperature was warm, and four nights after the full moon, when there was little tidal movement and the sun had set, nature’s conditions were just right for the annual phenomenon known as Coral Spawning on the Great Barrier Reef.
Coral spawning was unknown to science until 1982, when several marine biologists working on the Great Barrier Reef observed it in the wild for the first time.
Quicksilver marine biologist Russell Hore explains that while corals have two reproductive methods, asexual where the individual polyps split and divide to increase overall size of the colony, to maintain a consistently robust gene pool corals need to have a sexual phase to exchange genes. This process is known as coral spawning.
‘‘The majority of corals are hermaphrodites, which means they are both male and female at the same time. On the night of spawning, the polyps begin to expand out of their limestone cups and bundles of orange eggs can be observed.
‘‘By synchronising to reproduce at the same time, and putting most of their effort into a short period of the year, corals can maximise their reproductive effort.
‘‘Everyone is aware of the day after coral spawning. There is usually an orange slick on the water that has a certain aroma, and all the plankton feeders have bulging stomachs from feasting on the leftover unfertilised eggs.’’
Meanwhile, it was reported earlier this week a diver spent more than two harrowing hours treading water 40km out to sea after he became separated from a dive boat on Sunday night.
The man was reported missing after he failed to surface from viewing coral spawning at Michaelmas Reef, off Cairns, about 7.40pm.
Cairns Water Police Sgt Andrew Ibell said a vessel and rescue helicopter were deployed about 9pm to find the man following stormy conditions.
‘‘He became disoriented due to his dive and when he surfaced he was unable to see the vessel he was diving from,’’ he said.
‘‘The helicopter located the person in the water he had a dive torch and was able to signal the helicopter.
"It was a very lucky outcome for him being out there at night it was stormy at one stage and he had some signalling equipment.’’
Sgt Ibell said the man had drifted 800m from the vessel and had been in the water for at least three hours.
The dive boat was pointed to the man’s location where he was brought back aboard.
Sgt Ibell said water police were directed to a stranded 11m yacht at Fitzroy Island soon after the dive incident.
SPAWNING: becoming a staple Reef attraction