Latest Survey of ‘Coral Cover’ Fundamentally Unscientific

From Jennifer Marohasy’s blog

Jennifer Marohasy

According to the latest Australian Institute of Marine Science report, there is record coral cover at the Great Barrier Reef. Yet this is less than 30 percent at about half of the reefs surveyed.

The relatively low percentage cover is because only the reef perimeter is surveyed by AIMS, which is the equivalent of reporting on the population of Sydney after skirting around the outer suburbs.

Such a method (skirting around the outer suburbs) would give no indication of population trends in more densely populated inner-city areas. And so the latest AIMS report gives no indication of coral cover at reef crests, which for all we know given the methodology underpinning this latest survey, may have collapsed entirely across the Great Barrier Reef.

We cannot know.

Furthermore, despite advances in both underwater and aerial drone mapping, which could provide automated quantitative assessments by habitat with photographic and/or visual records, AIMS persists with a method that involves towing an observer who guestimates coral cover.

Their method is subjective and archaic. It is not scientific.

My early career was spent as a field biologist in Africa. If I had submitted the AIMS survey method as the intended survey method for any one of the many insect species that I monitored, my supervisors would have rejected it. Whether attempting to monitor changes in the population of an insect species, number of people in a city, or hard coral cover at the Great Barrier Reef, there are certain factors that need to be considered if the method is to be considered scientific and therefore reliable.

Key deficiencies in the current AIMS long-term monitoring program include:
1. Conclusions are drawn about overall coral cover at each reef without ever measuring coral cover at key habitats (E.g. at the reef crest).
2. Variability in coral cover is never quantified by habitat type (E.g. reef crest versus back lagoon).
3. The area surveyed at each reef (defined by AIMS as total ‘reef perimeter’ measured as sum of manta tows) incorporates results from different habitats, and as a consequence it is doubtful that the sample plan is adequate in terms of number of replications (manta tows) per treatment (habitat) at each reef perimeter.
4. Numerical values represent subjective guesses.
5. There is no photographic or video record enabling quantification of the accuracy of the guesses.

If we consider John Brewer Reef, as an example, most of the healthy coral grows over the reef crest where it exceeds 100 percent cover in many places. The corals at the reef crest grow on a sturdy limestone platform built up of layer upon layer of dead coral. This reef crest is about 9 metres above the reef perimeter in the northern lagoon where the corals grow amongst rubble and sand with coral cover much patchier. Because the AIMS long term monitoring program only surveys the perimeter, it has determined coral cover at this reef to be 22 percent. To be clear, there could be major mortality of corals at the crest, where most of the corals are, and yet this would never show up in the long-term monitoring results for John Brewer Reef.

I have shown the potential for an alternative method at Pixie Reef laying 10 metre photographic transects (instead of manta tows) repeated (replicated) at least 9 times (to enable quantification of within habitat variability) for three different habitat types (crest, back lagoon and reef front).

The photographs from these transects, and more information about the method, are at my Pixie Reef 2021 data page, that is here:

Fundamental to the success of any survey designed to detect change, must be a consideration of the distribution of the population of interest (E.g. corals by habitat or people by suburb) before attempting to quantify it – to count it. Only then is it possible to know with any level of certainty if there is any significant change in the overall population of the city or coral reef and/or some component of it.

It is unfortunate that so much time and money and diesel has been spent for so many years by AIMS, at the expense of the Australian tax payer, without any discussion or explanation of the method. Most people who take an interest in the results assume all the key habitats are surveyed, but they are not. They assume actual corals are counted, but they are not.

The feature image at the top of this blog post is an aerial drone photograph of Pixie Reef looking from the back lagoon across the reef crest to the reef front that is exposed to the dominant prevailing winds. Coral cover, and species diversity, vary significantly by habitat.

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August 10, 2022 2:43 pm

As I commented at your website Jennifer –

GBR health reports over the past 2 decades have been drafted for 2 distinct purposes –

1) doomsday headlines for the media;
2) to suck more funding from governments.

That is all.

Neil McLachlan
August 10, 2022 2:58 pm

The coral bleaching is caused by natural changes in cloud cover, resulting in changes in short wave radiation, sunlight.

Infrared radiation can not penetrate past the evaporation layer of the ocean so it can not have an impact on coral bleaching.

During an el nino relatively cool water collects on the western side of the pacific ocean, over the barrier reef yet this is when the majority of bleaching events occur. It is because el ninos cause a decrease in cloud cover over the barrier reef and an increase in sun light.

The Role of Clouds in Coral Bleaching Events Over the Great Barrier Reef | Request PDF (

I have been trying to get a copy of this paper for years but can’t. Probably because of the fear amongst Australian scientists after what happened to Peter Ridd

Reply to  Neil McLachlan
August 10, 2022 3:23 pm

During an el nino the average depth of the sea decreases slightly over the reef and there is an increase in short wave radiation due to lower cloud cover which is a double whammy for bleaching. During la Nińa the opposite situation occurs allowing corals to recover. Refer to articles by Jim Steele on this blog and paper by Indonesian Biigeosciences titled ” Ampou 2017″.

Neil McLachlan
Reply to  Dnalor50
August 10, 2022 4:12 pm

Yes, all natural, caused by natural climate events, ENSO and natural changes in cloud cover resulting in changes in short wave radiation.

Reply to  Neil McLachlan
August 10, 2022 6:09 pm
Neil McLachlan
Reply to  Paul
August 11, 2022 3:03 pm

Thanks heaps!

Rud Istvan
August 10, 2022 3:00 pm

This is hardly the only time that warmunists pre-selected their study method to give a predetermined answer.

  1. Want a hockey stick? Invent centered principal components ‘statistics’, which always produces one from any time series with red noise (meaning some underlying autocorrelation). Mann, before his ‘Nature trick’.
  2. Want sea level rise acceleration in fractions of mm? Use satellite observations having resolution in cm, then pretend repetition results in resolution to 0.1mm. NASA.
  3. Want summer Arctic sea ice to be disappearing? Use only satellite information starting in 1979 at a natural peak in the Arctic cycle. NASA.
  4. Want warming surface temperatures? Use stations corrupted by microsite issues (and UHI) and ‘ignore’ pristine CRN. NOAA.
  5. Want increasing forest fires? Just disappear all the USFS data before 1960. USFS and DoI.
  6. Want increasing tornados? Don’t mention the late 1980’s switch to doppler radar that ‘sees’ more of them. NOAA
  7. Want an ocean ‘acidification’ smoking gun? ‘Research’ the Whiskey Creek oyster hatchery spat set problem on Netarts Bay. It is NOT an estuarine environment but needed to be run as if it were. PMEL within NOAA. (Essay Shell Games in ebook Blowing Smoke.)
  8. Want to show catastrophic tipping points? Research Eemian high stand along West Australia, then ignore own data about an earthquake at Quobba Ridge and provide fig. 2 which is only Quobba Ridge. (Essay By Land or By Sea in ebook Blowing Smoke.)

And so on.

Gary Pearse
August 10, 2022 3:06 pm

Jennifer, were the AIMS folk not advising the reef was in terrible shape last year? I was wondering if the complete turnaround wasnt because of two things that shone a light on on their dark research. First, Peter Ridd’s firing from Cook U for accusing the coral researchers of sloppy work and unsupported conclusions. The international interest in this wasobvious from the GoFundMe response for the court case. Secondly for your following this up with dives, photography, articles and a film showing healthy coral where they had pronounced dead, plus your program of taking young people on dives to see the coral.

With the trust in science almost gone because of its servicing of political ends in exchange for gov cash rewards, citizen watchdog science is is essential, especially since they seem okay with destroying the world economy.

August 10, 2022 8:30 pm

Here she claims: Over the last two years I have supported Peter Ridd in his quest for some quality assurance of Great Barrier Reef science.

And: Whistleblower
During 2002-2003, I documented my concerns with the World Wild Fund for Nature (WWF) Save the Reef Campaign including the perverse influence of this campaign on public policy in a long review entitled WWF Says Jump, Governments Ask How High and a short piece for the IPA Review in March 2003 entitled, Deceit in the Name of Conservation.
During 2003-2006, I presented evidence suggesting that some within the Land and Water program at CSIRO had misled the Australian public on Murray River salinity issues. This work featured in a Channel 9 TV documentary with Ross Coulthard Australia’s Salinity Crisis: What Crisis.

Reply to  AntonyIndia
August 10, 2022 10:00 pm

CSIRO has become a complete joke if the latest drivel from the CE is anything to go by….. and it is….

Hoyt Clagwell
August 10, 2022 8:47 pm

“The relatively low percentage cover is because only the reef perimeter is surveyed by AIMS, which is the equivalent of reporting on the population of Sydney after skirting around the outer suburbs.”
Or is it the equivalent of reporting on the temperature of the entire Earth after surveying only the top two meters of an atmosphere 62 miles in depth?

Ireneusz Palmowski
August 10, 2022 11:08 pm

Sea level rise and upwelling during La Niña increases coral cover in the absence of tropical cyclones. As we know, this is the third year of La Niña.
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August 11, 2022 2:32 am

If surveying a reef from a boat are there permanent floating moorings rather than dropping anchor ?

Reply to  zemlik
August 11, 2022 6:23 am

zemlik the great barrier reef is not a sheet of coral. All lagoons & semi lagoons have large areas of mixed sediment bottom with scattered patches of coral. The more solid reefs have large areas of deep water between individual reefs, where there is no coral growth.

There is plenty of room for anchoring where no coral will be effected.

Reply to  zemlik
August 11, 2022 2:26 pm

If you can’t find a clear sandy bottom space between reefs, and you are in a small-ish boat, you can drop a “reef kellick” anchor, whose finger prongs are made of malleable metal, and which can be straightened and pulled free with a modest amount of tug on the anchor line.

Use floated anchor line though, not chain.

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August 11, 2022 6:32 am
  1. Before the global warming hoax gathered full steam in the 1990s, the Reef doomsday society blamed the nasty farmers for contaminating the water of the Coral Sea. On many occasions I have requested water analyses fro learned institutions (GBRMA, CSIRO, JCU and ANU). Every single request was ignored. I strongly suspect that any effects to water quality from chemicals used in farming are too low to be measured. ie NEGLIGIBLE.
  2. If the Reef doomsday society believes that the latest survey is meaningless because of its methodology then it must follow that the previous 39 years of surveys have all been meaningless for the very same reason.

Some of these blokes (and ladies) wash themselves too quickly in the shower.

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