Reef Report for Friday, November 8, 2002
Warm Ocean Temperatures Herald Coral Spawning
With the summer weather in full swing and the water temperature on the reef on the rise one major event that will be taking place is Coral spawning. The coral on the Great Barrier Reef, like all other life forms, reproduces to maintain or increase their numbers.
Commonly expressed as "Sex on the Reef", this event happens once a year at night during the months of November and December. This year the dates predicted for coral spawning should be between the 22nd and 26th of November. Each year the big question is "Exactly when will coral spawning occur?". There is no exact answer, as a number of conditions need to by right, with twater temperature being a major factor.
I have yet to be lucky enough to be out on the reef when coral is spawning. As this event comes closer I will list the individual day boat operators putting on a special night dive trips just for coral spawning. So stay tuned for information on this event or contact local dive operators to see if they are planning a special trip. As all liveaboard dive operators will already be out there it is a good opportunity for time out on the reef. This special event is not just for divers; snorklers also can enjoy at great night of snorkeling and see the coral spawning.
It is not only the corals that are in on the action. Crustaceans, molluscs, fishes, cucumbers etc, all reproduce around the same time as the corals. The titan triggerfish are defending their nesting sights at this time. The female lays many batches of eggs between November and February. Twenty-four hours after laying her eggs, she blows the juveniles out to sea to colonize on other reefs. During these nesting periods, she is phenomenally aggressive and divers should keep their distance from their nests. In between laying each batch she becomes passive again.
Here’s what has been happening out on the reef this week:
Another great week diving & snorkeling with Calypso was had on the Outer Barrier Reef. Passengers enjoyed sightings of lots of Queensland grouper and pods of dolphins.
Introductory divers this week on board Passions of Paradise at Paradise Reef saw a school of moon wrasse as well as a Bluestreak Goby fish in 6 metres of water. Certified divers were lucky enough to swim along side a school of chevron barracuda and also reported seeing a Titan Triggerfish in 12 m of water while Snorklers saw some sea stars as well as some bright giant clams. Visibility was between 15 and 20 meters with calm surface conditions.
Reef Magic Cruises this week visited Saxon and Hastings Reefs, reporting very pleasant conditions with visibility around the 20 metres and an abundance of marine life. There were plenty of white tipped reef sharks and turtles were out on show for everybody. I have enjoyed many wall dives at Saxon Reef, which is a great dive site and is certainly well worth a trip out.
Coral Sea/Ribbon Reefs:
Divers on board Taka II again received some excellent diving conditions during the week. A large school of trevally and a 5-foot Dog Tooth Tuna were sighted at Osprey Reef. A good number of grey whalers, white and black tipped reef sharks came in for the feed as well.
Diving at the Cod Hole produced a nice sighting of 5 huge potato cod and then on the other extreme a beautiful tiny Dusky Nembrotha (a nudibranch) at Pixie’s pinnacle. The sightings at Steve’s Bommie at the Ribbons Reef included stonefish, lionfish and a Wobbeygong Shark.
Water temperature is a pleasant 27 degrees in most areas and winds appear to be remaining around 20+ knots. Beautiful sunshine looks like it is set to continue at the reef into the weekend but it could be a bouncy trip out. So take the necessary precautions and you will still have a great day diving or snorkeling.
So have a great weekend and as always safe diving, Steve Brady.
This weekly reef report was written by Steve Brady of Pro Dive Cairns, who compiles them from the dive trips he takes, as well as the many conversations he has with divers, dive instructors, captains, and others in the Cairns dive community. The report is published weekly in the Cairn Post, the local daily paper and appears here thanks to the courtesy of
Pro Dive Cairns.
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