Reef’s big night’s a star

Port Douglas & Mossman Gazette - - FRONT PAGE -

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

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