Coral Snapshot 2022-23, & All the Unanswered Questions

Full marks to David Mills, writing in the Courier Mail, for asking why the government tends to bury good news reports about the Great Barrier Reef.

There are a few other questions that I would like answered.

Key government ministers, marine scientists, and climate scientists have been unable to acknowledge:

Q1. Overall coral cover has been increasing since at least 2009 (14 years).

Q2. According to official underwater surveys – that are perimeter surveys – coral cover is at a record high.

Q3. These perimeter surveys under estimate coral cover, claiming it to be less than 30%, when coral cover is often more than 90% at the crest of the same reef.

Corals around the outside/perimeter of reefs are particularly susceptible to cyclone damage.

Q4. The number and intensity of cyclones has been decreasing since at least the 1970s. Something the Bureau of Meteorology is unable to acknowledge. Why?

This chart never makes it into any of the high profile 'State of the Climate or Environment' reports.  It shows that both the number and severity of tropical cyclones has been in decline since the early 1970s.

Q5. When will the Australian Institute of Marine Science (AIMS) reconcile results from aerial surveys that report severe bleaching (30-60%) with underwater survey results that reported no (0%) bleaching – at the same coral reefs at the same time?

For example, aerial surveys of John Brewer Reef in March 2022 reported 60% bleaching. Coincidentally, at the same time this reef was being surveyed underwater. The results published online in August 2022 found no coral bleaching at this reef (o%).

It is impossible to reconcile 60% bleaching based on the official aerial survey with 0% bleaching based on the official underwater survey for John Brewer Reef, with both surveys undertaken in March 2022.

Results from underwater survey are here:

Results from aerial survey were here:

Since removed.

There never were any photographs from the aerial surveys, and the results have since been removed, without explanation.

I visited John Brewer reef in April 2022 after it made worldwide headlines as the centre of mass coral bleaching. I found a coral wonderland, with one of the underwater photographs from that visit featured at the top of this blog post. At the reef crest coral cover exceeded 100%, with corals growing onto of each other. Meanwhile, the official underwater survey stated coral cover to be just 21.8%.

To be clear, John Brewer Reef, that was being reported around the world as stark white, was, in reality, the most beautiful coral reef with over 100% coral cover at the crest, and an abundance of fish and other marine life including a friendly white tipped reef shark.

I detailed the extent of the contradiction in a series of blog posts, including ‘Stonewalling on Contradictory Results – Part 3: John Brewer Reef Fact Check’.

I also made a documentary film, entitled ‘Bleached Colourful – Part 1’ it shows the corals at John Brewer reef in April 2022 from both under-the-water and from my own aerial drone survey.

David Mills, writing in the Courier Mail, is referring to a more recent ‘Snapshot report’ about the Great Barrier Reef that concludes:


While sea temperatures in spring were the hottest on record, summer sea temperatures were at or slightly above average.

Data on sea temperatures are theoretically available from approximately 80 Great Barrier Reef sites, 16 Coral Sea sites, 7 sites in Northwest Western Australia, 8 Queensland regional ports, 13 sites in the Solitary Islands, 4 sites in PNG and 10 sites in the Cocos (Keeling) Islands. Data are obtained from in-situ data loggers deployed on the reef. Data loggers instantaneously record sea temperatures every 30 minutes and are exchanged and downloaded approximately every 12 months. Except not one of these temperature series are ever shown by the Australian Institute of Marine Science so we can see the actual temperature data as a continuous time series – unadjusted.


Minor bleaching was seen in all three regions (northern, central and southern), however there was no mass coral bleaching.

I was recently diving off Cairns and there was absolutely no bleaching. Ace underwater photographer Stuart Ireland is consistently filming above and below the water and he can report that the reef is in magnificent condition. He regularly posts video at


No cyclones entered the Marine Park. Large swells from TC Gabrielle which tracked outside the Reef in February may have caused some damage to some reefs on the outer edge.


Crown-of-thorns starfish outbreaks continue on reefs in the southern region, particularly in the Swains reefs.

The Swain Reefs include about 400 individual reefs covering an area of 16,900 square kilometres (4 million acres), that is about 120 nautical miles off shore (about 220 kms).

The Swain Reefs have historically sustained high numbers of these starfish, and regular outbreaks, probably for thousands of years.

Natural predators of crown-of-thorns star fish include the giant triton snail and titan trigger fish. They gobble up the star fish, that are native to the Great Barrier Reef.

Giant triton snails are particularly efficient at devouring crown-of-thorns starfish never mind the sharp spines, as shown in this video courtesy of the Australian Academy of Sciences.

I have been diving and snorkelling the Great Barrier Reef for more than 50 years, and one of my favourite fish is the Titan Trigger Fish, that I recently photographed lying across a bed of soft corals at Saxon Reef off Cairns.

Can you see the Trigger fish lying across the soft corals? I took that photograph on about 1st April 2023.
The Trigger fish that I swam with at Saxon reef, off Cairns.

I’ve seen these fish, that have large teeth, flip crown-of-thorns starfish onto their backs before eating out their soft underbelly, as shown in this YouTube.

via Jennifer Marohasy

May 19, 2023 at 06:55PM

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