From Jennifer Marohasy’s weblog
Jennifer Marohasy
Based on the newest Australian Institute of Marine Science report, there may be document coral cowl on the Nice Barrier Reef. But that is lower than 30 p.c at about half of the reefs surveyed.
The comparatively low share cowl is as a result of solely the reef perimeter is surveyed by AIMS, which is the equal of reporting on the inhabitants of Sydney after skirting across the outer suburbs.
Such a technique (skirting across the outer suburbs) would give no indication of inhabitants developments in additional densely populated inner-city areas. And so the newest AIMS report provides no indication of coral cowl at reef crests, which for all we all know given the methodology underpinning this newest survey, might have collapsed completely throughout the Nice Barrier Reef.
We can’t know.
Moreover, regardless of advances in each underwater and aerial drone mapping, which may present automated quantitative assessments by habitat with photographic and/or visible information, AIMS persists with a technique that entails towing an observer who guestimates coral cowl.
Their technique is subjective and archaic. It isn’t scientific.
My early profession was spent as a discipline biologist in Africa. If I had submitted the AIMS survey technique because the meant survey technique for any one of many many insect species that I monitored, my supervisors would have rejected it. Whether or not trying to observe modifications within the inhabitants of an insect species, variety of individuals in a metropolis, or laborious coral cowl on the Nice Barrier Reef, there are specific components that have to be thought-about if the tactic is to be thought-about scientific and due to this fact dependable.
Key deficiencies within the present AIMS long-term monitoring program embrace:
1. Conclusions are drawn about general coral cowl at every reef with out ever measuring coral cowl at key habitats (E.g. on the reef crest).
2. Variability in coral cowl is rarely quantified by habitat kind (E.g. reef crest versus again lagoon).
3. The realm surveyed at every reef (outlined by AIMS as complete ‘reef perimeter’ measured as sum of manta tows) incorporates outcomes from totally different habitats, and as a consequence it’s uncertain that the pattern plan is enough when it comes to variety of replications (manta tows) per remedy (habitat) at every reef perimeter.
4. Numerical values characterize subjective guesses.
5. There isn’t a photographic or video document enabling quantification of the accuracy of the guesses.
If we contemplate John Brewer Reef, for instance, a lot of the wholesome coral grows over the reef crest the place it exceeds one hundred pc cowl in lots of locations. The corals on the reef crest develop on a sturdy limestone platform constructed up of layer upon layer of lifeless coral. This reef crest is about 9 metres above the reef perimeter within the northern lagoon the place the corals develop amongst rubble and sand with coral cowl a lot patchier. As a result of the AIMS long run monitoring program solely surveys the perimeter, it has decided coral cowl at this reef to be 22 p.c. To be clear, there could possibly be main mortality of corals on the crest, the place a lot of the corals are, and but this might by no means present up within the long-term monitoring outcomes for John Brewer Reef.
I’ve proven the potential for another technique at Pixie Reef laying 10 metre photographic transects (as a substitute of manta tows) repeated (replicated) no less than 9 instances (to allow quantification of inside habitat variability) for 3 totally different habitat varieties (crest, again lagoon and reef entrance).
The pictures from these transects, and extra details about the tactic, are at my Pixie Reef 2021 information web page, that’s right here: https://jennifermarohasy.com/coralreefs/pixie2021/
Basic to the success of any survey designed to detect change, should be a consideration of the distribution of the inhabitants of curiosity (E.g. corals by habitat or individuals by suburb) earlier than trying to quantify it – to depend it. Solely then is it doable to know with any stage of certainty if there may be any vital change within the general inhabitants of town or coral reef and/or some element of it.
It’s unlucky that a lot money and time and diesel has been spent for thus a few years by AIMS, on the expense of the Australian tax payer, with none dialogue or rationalization of the tactic. Most individuals who take an curiosity within the outcomes assume all the important thing habitats are surveyed, however they don’t seem to be. They assume precise corals are counted, however they don’t seem to be.
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The function picture on the prime of this weblog submit is an aerial drone {photograph} of Pixie Reef trying from the again lagoon throughout the reef crest to the reef entrance that’s uncovered to the dominant prevailing winds. Coral cowl, and species variety, fluctuate considerably by habitat.
