Quicksilver Group News

Exciting Night Dives and Coral Spawning on the Great Barrier Reef

With the water temperatures warming and the November full moon approaching, the crew aboard our Silverswift dive and snorkel adventure boat are gearing up for the sex on the reef – annual Coral Spawning on the Great Barrier Reef that is!

Silverswift will once again be conducting exciting Night Dives for certified divers to experience this unique natural phenomenon of coral spawning, which this year is predicted to occur by our marine biologist experts around 22 – 24 November.

Based from Great Adventures’ Norman Reef platform, certified divers can do two guided night dives while experienced snorkellers can also participate with a guided tour. In addition to the thrill of night diving and the potential of witnessing coral spawning, there’s a whole new cast of nocturnal reef life to be seen on the “night shift”!

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 to maintain a consistently robust gene pool, corals need to have a sexual phase to exchange genes and this is the process known as coral spawning.

“Predicting when this will occur is not an exact science but does rely on several environmental cues. The ocean temperature needs to be 26 degrees celcius or above for the month before for the gametes to mature. Secondly, they will generally reproduce 4 to 6 nights after the full moon in November or December when there is little tidal movement. Thirdly, it will generally be about 2-3 hours after the sun sets, because it’s nice and romantic (!), but more importantly most of the plankton feeders will be asleep, giving the eggs more time to settle to the relative safety of the reef.”

“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 synchronizing to reproduce at the same time, and putting most of their effort into a short period of the year, corals can maximize 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 unfertilized eggs.”

Silverswift’s Coral Spawning Night Dives will depart Cairns at 5.30pm to the Outer Reef and return at 11.15pm, 22, 23 and 24 November 2013.

While coral spawning is not guaranteed, our marine biologist experts predict the best potential conditions will occur around 22-24 November 2013.

Bookings and enquiries for Silverswift’s Coral Spawning Night Dives:
4044 9944 or www.silverseries.com.au

Click to Download the Coral Spawning 2013 Flyer