The Reef Abides … Or Not

Guest Post by Willis Eschenbach

I’ve written a few times on the question of one of my favorite hangouts on the planet, underwater tropical coral reefs. Don’t know if you’ve ever been down to one, but they are a fairyland of delights, full of hosts of strange and mysterious creatures. I’ve seen them status and trends of caribbean coral reefsfar from the usual haunts of humanoids, where they are generally full of vigor and bursting life.

I’ve also seen them in various stages of ill-health, including the bleaching caused by occasional high temperatures (which a healthy reef recovers from in a few years). In all of my writings on this subject, I’ve said that the health of the reef depends in large part on parrotfish. I’ve proposed that atoll nations declare the parrotfish as their national bird, just to bring attention to the fish that are responsible for the very existence of the atolls themselves.

This is for two reasons. First, parrotfish are herbivores. They graze on the algae that is constantly trying to take over the reef. This keeps the reef clear of algae so that the coral polyps can get the sunlight that they need to survive.

Second, the parrotfish graze by biting off chunks of coral. They crunch these up between specialized bony plates in their throats, digest all of the greenery, and they subsequently excrete nothing but the finest, whitest, softest coral sand … the very sand that makes the romantic tropical beaches. It’s quite funny to see what happens if you disturb a whole school of them—they drop their entire load and disappear in a flash, leaving nothing but a white cloud of sand slowly dropping to the ocean floor, eventually to be swept by the waves up onto the beach.

Unfortunately, although parrotfish are wary during the day, they sleep at night out in the open. As a result, the advent of the waterproof flashlight has led to their local extinction on many reefs.

To bring this story up to the present, over at his excellent NoTricksZone website, Pierre Gosselin points out a press release from the International Union of Concerned Scientists (IUCN) entitled From despair to repair: Dramatic decline of Caribbean corals can be reversed. It discusses a recent report called “Status and Trends of Caribbean Coral Reefs, 1970-2012”, linked to below.

status and trends of caribbean coral reefs

In the press release, they point out that although climate change has been blamed for the decline in Caribbean coral reefs, the major reason for the decline is … drum roll … the loss of the parrotfish and other reef grazers. The press release says:

Climate change has long been thought to be the main culprit in coral degradation. While it does pose a serious threat by making oceans more acidic and causing coral bleaching, the report shows that the loss of parrotfish and sea urchin – the area’s two main grazers – has, in fact, been the key driver of coral decline in the region.

Despite the obligatory nod to climate change, they have finally come to their senses.

Now, the IUCN has been heavily invested in the “climate change” meme, so I find this to be a most welcome sign that perhaps some sanity is returning to the field. Back a decade ago I wrote about role of parrotfish in reef loss, but at that time everyone from the Sierra Club to the IUCN were blaming climate change.

And this is one of the huge problems with blaming everything and its cousin on climate change—when you blame wrongly climate change, you ignore the real problem. For example, the claimed (but illusory) “sinking” of coral atolls was long blamed on sea level rise from climate change.

But all that did is obscure the real danger to coral atolls, which is the decline of the reefs on which they depend for their continued wellbeing. Regarding the Caribbean reefs, the report itself says:

Outbreaks of Acropora and Diadema diseases in the 1970s and early 1980s, overpopulation in the form of too many tourists, and overfishing are the three best predictors of the decline in Caribbean coral cover over the past 30 or more years based on the data available. Coastal pollution is undoubtedly increasingly significant but there are still too little data to tell. Increasingly warming seas pose an ominous threat but so far extreme heating events have had only localized effects and could not have been responsible for the greatest losses of Caribbean corals that had occurred throughout most of the wider Caribbean region by the early to mid 1990s.

So … will the reefs abide? Fortunately, we now know that waving our hands at CO2 is not the solution to the problems of the reefs—as with far too much of such CO2 hysteria, the underlying problems indeed have human causes, but they have nothing to do with CO2.

And that’s great news, because although we have no hope of changing atmospheric CO2, we can indeed do something about overfishing of parrotfish, and about coastal pollution. Fix those, and we’ll fix the reefs, and they will abide.

Best regards to everyone, and thanks for all the parrotfish, I’m off for Las Vegas.


Yeah, yeah, you already know this: The usual polite request. If you disagree with something, quote the exact words. Only in that way can we understand what you disagree with.

My previous posts on the subject:

Floating Islands

The Irony, It Burns

The Reef Abides

IUCN Press Release: From despair to repair: Dramatic decline of Caribbean corals can be reversed

IUCN Report: Status and Trends of Caribbean Coral Reefs: 1970-2012


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Fishermen used to feed parrot fish off the Sound in Bermuda with bread. They were big and friendly. But coming into contact face on while with a mask on, they look like whales. I think I broke an Olympic record swimming back to shore? LOL. Bermuda is one big tropical fish tank.Very warm waters.

stan stendera

Bravo! For ten years parrotfish have been ignored because of warming hysteria and you are by no means the only person pointing it out for ten years. Stupid is as stupid does.
Have fun in Vegas. It looks like quite a conference.


Bermuda is surrounded by reef, that keeps large sharks and barracuda out. However, the water near the shore is really tepid in summer. Spoiled me from bathing in Australia and never in England again. The warmer waters as I have said is like bathing in a tropical fish aquarium this was in 1969. Doubt if the waters have warmed any more as they are tidal. One could tread water in the Harrington Sound without getting cold for hours.


Water temps are around 26 – 30 C. (Tropical fish tank temps. But one blog told some porkies, saying that they bathed in the mouth of rivers? No rivers in Bermuda, canals though man made with luxury homes belonging to billionnaires. No tax in Bermuda for companies registered there. Most water is collected in underground tanks and if rain misses this narrow island, it is bought in or from the recycling water from hotels.

John F. Hultquist

I pointed out on Pierre’s site that the authors are not ready to give up their funding and so make the following statement: “Climate change . . . does pose a serious threat by making oceans more acidic and causing coral bleaching,


Reefs in the Indonesian Pulau Seribu regularly see water from the back reef flow on out in the afternoon. The water is bathtub warn or hotter, so hot it causes an optical distortion. We are talking 10’s of degrees, not tenths.
All the Acropora has died. I doubt is was from climatic warming—-over fishing?? probably.


You forgot dynamite fishing and cyanide fishing and the crown of thorns starfish which I have seen devour huge swathes of reef in the Indian Ocean, pre tourism.
Agree Willis.

A Great Post, Willis! The bogey of Global Warming is more and more frequently used as an explanation for all problems and as a result people fail to look for the real cause and employ real solutions. Parrot Fish loss is just one example of many causes hidden by Global Warming hysteria.


Please enable animation which shows the drop in temperature in the southern oceans (larger absorbs CO2).


The animation shows the carbon monoxide (especially in the Amazon). Sorry.
Reply: Would you like me to delete both comments? ~mod


There are many reasons to disagree with so called liberals/progressives, but the thing that gets to me the most is there insistence on not providing solutions. They relish problems.
While they kvetch about shrinking coral reefs, would they offer to breed parrot fish ?
In New England they shut down many fishing areas to protect fish stocks, but do they offer breeding the fish that they claim are becoming extinct.
In CA, the government clamps down on water use, but do they ever discuss building desalination plants?
All problems, no solutions.


It does not matter, because the carbon monoxide reacts with oxygen.


Willis– I really appreciate your very informative posts that you’ve made over the years on parrotfish and their integral role in keeping coral reefs healthy.
My wife and I have done a lot of diving in Okinawa, Japan and off the coasts of Guam, Hawaii and Saipan. You’re right about the other worldliness of the experience! The second you drop your face mask into the water, it’s like you’ve been teleported into another mesmerizing parallel universe.
You’ve gotten me many laughs when I inform people playing in white pristine beach sand that they’re actually playing with parrotfish poo…
Like all disinformation (which is FAR more harmful than misinformation), the CAGW hypothesis has definitely helped speed up the destruction of Pacific coral reefs. Had island governments stopped trying to extort CO2 reparations and simply set a $1,000 fine for anyone caught killing/selling parrotfish, their coral reefs would be much healthier than they are now… But, alas….
Here is an idea, if you could put together a short Powerpoint presentation, I, and I’m sure many other WUWT readers, would be happy to forward it to a number of Pacific-island government officials…
I’m not sure if it would help, but, in the spirit of the Cajun philosophy of life, “Ya neva know.”
Anyway, thank you for your posts. I always enjoy them.

Lawrie Ayres

Samurai writes of disinformation. It is far more dangerous than misinformation that usually results from ignorance. The former is an intelligence tactic used to mislead an enemy. AGW adherents use it to mislead the populace whom, by extension, they must consider the enemy. I wonder will the dis-informers ever be held to account? They should face public humiliation at a minimum.


Thanks, Willis.
Just last week, I was snorkeling on the Hawaiian coast (two different Islands). A healthy reef is a sight to behold, and I was amazed watching the various grazers. I am not sure how the various species vary from the Pacific to the Caribbean, but the ecosystem clearly depends on the presence and health of the fish.
Sadly, as with so many environmental issues, assigning the blame first and primarily to CO2 draws public attention away from much more urgent and important matters.

Don K

Some minor points re tropical coral reefs.
1. Does anyone but me think that it is curious that the reef problems blamed so easily on “climate Change” are occurring in the regions that climate modeling tells us will be least affected by climate change?
2. One of the consequences of warming — regardless of the unsubstantiated possibility of damaging some tropical reefs in the warmest waters — should be poleward expansion of coastal reefs such as those off Southern Florida and Australia’s Great Barrier Reef. I have looked on the internet for evidence this is actually taking place. Lot’s of papers/articles but almost all are science fiction/science fantasy. “Climate change might …” or (all to often) “climate change will …” But I’ve only ever found one paper by folks who have actually gone and looked at the reef. Their conclusion — The South Florida reefs have not expanded North of their traditional boundaries. One paper isn’t enough to draw conclusions from and their could be all sorts of reasons that particular reef isn’t expanding poleward — pollution, cold currents, etc. But still …
Anyway, I personally think our great grandkids will very likely inherit a planet where humans have done a lot of environmental damage. But I’m very skeptical that coral reefs overall are going to be very different than they are today or were in Charles Darwin’s time.

Mick In The Hills

Parrot fish are not bad to eat fresh, but they don’t refrigerate or keep very well. So I can’t grasp why they would be a commercial target species.


The coral reefs I have seen in the best health are loaded with parrot fish. Healthy reefs tend to be either in places where there are no people, or where fishing is prohibited. Those in poor health have few or no parrot fish. Where the reefs are dying is usually where local (often quite poor) people have been fishing them heavily. Education of people combined with fishing regulations will help, but the best solution is to reduce poverty in regions where there are coral reefs. (And everywhere else for that matter.)


Original post retains award for Best Post Title Ever. Nice.

mac d

Thanks for this post. Maybe we can redirect most of the $3billion spent on CAGW tom-foolery and spend it on real issues.

Leo Morgan

While I don’t support the claim that sea-level rise will doom Pacific Island Nations, it seems self evident to me that tsunamis will intermittently scour these islands of human life.

Dave Worley

Yes, the #1 problem with the Climate Change “crisis”.
Science is failing to address local problems which can be solved by conventional solutions.
Valuable minds are being wasted chasing trivial facts about melting ice and such.


Willis: The IUCN is the International Union for the Conservation of Nature


o/t by necessity – here’s the good news from Australia tonite our time:
7 July: Ninemsn: Carbon tax likely to be scrapped in days
There was a false start, a few hurdles and a marathon debate but the government eventually got the carbon tax repeal on the agenda for the first day of the new Senate.
It means the repeal is likely to pass within days, with debate to continue on Tuesday…
The government got its way after moving to suspend standing orders twice, eventually winning the crucial support of PUP and Senator Muir…
The coalition was backed by PUP’s three senators, Senator Muir, Liberal Democrat David Leyonhjelm and Family First’s Bob Day.
They are the same six senators expected to give the government the six votes it needs to pass the repeal…


Love the Douglass Adams reference in the sign-off.


A look at bikini atoll where the coral grows like trees and is in pristine condition where man hardly goes would be enough to illustrate that the climate has very little to do with the state of coral.

Willis Eschenbach

Mick In The Hills says:
July 7, 2014 at 3:30 am

Parrot fish are not bad to eat fresh, but they don’t refrigerate or keep very well. So I can’t grasp why they would be a commercial target species.

You’re right, Mick. Typically they are targeted by artisanal fishermen who are spearfishing for food for the family, or for sale in some local village market … or, tragically, by tourists just out for a “good time”.


small, low cost mono-filament nylon gill nets + poor local fishermen = extermination of reef fish.
low-cost household bleach is also widely used to fish the reefs with devastating effect.


Here’s a web site that doesn’t blame global warming … yet
I’ve been SCUBA diving for 50 years and what I have noticed is that the closer the reefs are to people, the more degradation they seem to suffer. Parrot fish and sea urchins first started disappearing in the Caribbean near populated areas. The same in the Pacific around the Hawaiian islands. Coral damage was worst around population centers.
The die offs of stag horn and elk horn in the Caribbean that I have seen were caused by various diseases. The diseases did not seem to be correlated to water temperatures. Some of the bigger die offs started in the winter months with cool water temps. The lack of coral regrowth was inhibited by under grazing [the usual herbivores were gone] and there was an over abundance of damselfish species that cultivate algae.
My opinion … we ate the predators that controlled various fish populations , we ate the parrot fish and other reef grazing fish, we polluted the waters near population centers, we collected the triton trumpet that controlled the crown of thorns starfish. We released pacific fish species [lion fish] into the Caribbean. We changed the ecology of the reefs.
Lately, in some protected areas, of the reefs seem to be improving. Elk horn and stag horn are beginning to regrow, there are more sea urchins grazing the reefs and some of the predator fish are returning.
I believe we are causing reef destruction, but not by heating the sea water or changing the pH of the sea …

some of the finest diving I’ve seen in the world is in a very heavily used tourist location. Puerto Galera, PI is one of the finest hurricane holes in the world. The reefs are protected and fishing is banned. The corals are amazing, as are the reef fish. Delicate fan corals 10 feet, that are otherwise the fist victim of dynamite fishing. The fish are equally gigantic, growing to hundreds of pounds in the absence of fishing pressure. More amazing, they are used to humans not hunting them, and will allow you to approach within 2-3 feet before moving away. It is an amazing experience to swim with a school tropical fish, each 3-4 feet across.

A hat tip to the “Old Timers Club” in Puerto Galera for the some of the most fantastic diving this old timer has seen in the world. The drift dive we did along the slot canyons of the reef face was fantastic.

cal smith

My wife grew up in Tahiti before it had an airport. I visited it for the first time in 1966. I have spent many hours snorkeling in the coral lagoons (no need to use scuba gear because the water was so clear). When we went there on our honeymoon I took my wife to see one of the most beautiful sights I have ever seen – a bay with black sand covered with sea anemone of multiple hues. My wife said it was one of her favorite spots because her mother would take her there to visit with James Norman Hall’s widow. In the previous two years there had been a tourist hotel opened on the bay. Where formerly surface water activity was limited to dugout canoes, the area now was a bee hive of power boats and water skiers. The sand and silt being constantly stirred up and pollution from the hotel had killed all of the sea anemone and the underwater visibility was limited to a couple of feet. The last time we visited Tahiti (1982) we found that almost all of the coral inside the barrier reefs had been similarly killed. So many real ecological problems in the world are not being addressed because so much funding is directed toward the quixotic quest of controlling the weather- it is tragic.

Save the Coral Reefs – adopt a Parrot Fish!
It is interesting to note that Parrot Fish are found at coral reefs worldwide.
Wonder if there is an effort to “farm” them and then release them near appropriate reefs?

In SE Asia, the dead reefs are all the same. Overgrown with algae and urchins, with no fish to be found. Naturally bleached reefs are not dead, as it is usually only one species of coral that bleaches at a time, and the bleaching quickly disappears as new polyps colonize the affected areas.
Free swimming polyps are everywhere in the ocean and are continually looking for a solid, clean location to attach to and complete their life cycle. A bleached reef is a prime location to colonize. An algae overgrown reef on the other hand is not, as the polyps cannot attach to the algae. Without a grazing species like the parrot fish, the urchins by themselves are not able to clear the reefs of algae.

Uh, “parrotfish”.

On a healthy reef, there are fish everywhere and few urchins. the same is true on a bleached reef. On a dead reef however you find no fish and spiny black urchins in the thousands.


Im sorry Wilis!
For me you showed a completely different face than what I expected from you. Double standards when it comes to how to respect others compered to your own work and theories. When you are one of my now former favourite skeptics acts with the level of poison and accusational tone I disrespect the counerpart for it becomes hard to trust anyone about anything. You acted like you where an respectful non prestidigous open mind guy, but now I understand your not! You can keep your bloodfights and its audiences im not intrested in participation any more. You really let me and a lot of others down Willis! Remeber your reaction when R Spencer critizised you?
Dont treat others any different that you want to be treated Yourself Willis!”

Chris Schoneveld

Leo Morgan says:
July 7, 2014 at 5:28 am
While I don’t support the claim that sea-level rise will doom Pacific Island Nations, it seems self evident to me that tsunamis will intermittently scour these islands of human life.
Although it is true that coral reefs can easily keep up with sea level rise, the inhabited coral islands in the Pacific with their fixed infrastructures are not allowed the natural processes that keep these island above water because the natural build-up of coral sand that keeps these islands a couple of meters above sea level will not be allowed by the inhabitants. So the inhabitants will soon find out that the fixed infrastructures will be flooded more regularly as time (and sea level rise) progresses.

a major threat to coral is silt from rivers due to logging, land clearing and development. Corals need clear salt water. Silt smothers the reefs.


Even Nick Stokes has admitted that SG was right (probably fabricated data).
Now is the time to get a Court Order for NASA, USCHN etc to release all documentation pertaining to the USA temperature records. I wonder if we will get any admission from Zeke, Mosh credibility test…ect


You don’t eat Parrotfish.
Parrotfish eat corals which contain neurotoxins – harmless to the Parrotfish, but deadly to humans.
Some Islanders have developed an immunity over time, but a tourist who eats Parrotfish is like someone eating Fugu that has not been prepared by a master sushi chef – they are chancing their lives.


Willis…was back in Bermuda snorkling in 2012…over 20 years since my last visit.Georges Bay.The most disturbing thing I saw was the lack of any fish! No parrots,no cudas,just a few “Nemos”.Any coral reef needs some grazers.I wonder how many native Bermudans even realize that soft,white beach they are lounging on is fish poo?


It’s fascinating to me to realize that I had always assumed parrotfish were destructive to a reef because they nipped at and ate the corals (an assumption undoubtedly stemming from my preference to side with the corals from my saltwater reef aquarium days). Thanks for the information, Willis. You never know what misconceptions you hold until you listen to a different point of view.

Chris Schoneveld

If a reef is bleached it is due to a lack of unicellulair algae called zooxanthellae. The coloration of a healthy coral is due to microscopic zooxanthellae living within the coral’s tissue. So bleached corals can still be alive but are devoid of the symbiotic zooxanthellae algae.


Slabadang says:
July 7, 2014 at 7:30 am
Whatever are you nattering about? Did you put some questionable chemicals in your morning coffee? 🙂


Such anomaly sea temperature the action will magnify the cyclone, which glides over Japan.,38.96,728

Tom J

July 7, 2014 at 12:01 am
You’ve brought up a very important point. Once aquarists learned about the ammonia-nitrite-nitrate cycle the saltwater aquarium hobby exploded in the 1980s. For poorer people in reef areas the collection of tropical marine fish became an important supplemental income. The easiest way for them to catch these fish was with cyanide. The captured fish usually died a short time later in the aquarists’ tanks and, most importantly, the residual cyanide was devastating to the reefs. Laws were passed in many of these areas to prohibit this action but officials were oftentimes bought off. The hobby itself attempted to become self-policing and teams were sent to the regions to educate the locals to only employ the use of hand nets in capturing fish for the trade. I don’t know what the long term success was.
This posting by Wiis Eschenbach is an example of how thoughtful people, who have actual experience in matters, can propose viable solutions to life’s problems, and encourage others to add their own knowledge as well. It’s quite the antithesis to the immature and thoughtless global warming meme. As this parrotfish story illustrates the world is far more complicated (but, also simpler) than a one size fits all answer.


Slabadang says:
July 7, 2014 at 7:30 am
Im sorry Wilis!

Would it help if he shows his parrotfish/reef health data and math?