[Coral-List] Caribbean reef decline, reality and fairy tales

[Martin Moe]

Apologies for the long post, but I need to express myself on
the topic of Diadema. The great importance
of Diadema to the health of tropical western
Atlantic coral reefs is coming to the fore, but it is old news. The following
is an excerpt of text written by Doug Faulkner from an excellent book, Living
Corals, by Douglas Faulkner and Richard Chesher published in 1979, five years
before disease decimated the immense populations of Diadema throughout this
great area. 
 
“One morning I dropped anchor next to a large patch reef off
the southern coast of Eleuthera in the Bahama Islands. The water was clear and
I could see the yellow and orange of the shallower corals even before I leaped
in with mask and flippers. It was a magnificently healthy reef with the coral
growth as prolific and diverse as any I had seen. It was surprising, actually,
because I had just come from a patch reef not 100 meters away that was very
unhealthy looking. While the healthy reef swarmed with a great variety of fish
and invertebrates, the unhealthy one had a bleak look. It was covered with many
large dead corals, and the few remaining smaller ones were being smothered by a
thick coating of a broad-leafed algae.
 
A comparison of both reefs showed one major difference: sea
urchins. The healthy reef was loaded with sea urchins. Long, black spined Diadema, green Echinometra, small Lytechinus,
all tucked away in the coral waiting for night.. The other reef had no urchins at
all, not even small ones.
 
Sea urchins make up the maintenance crew that keeps algae
from becoming too abundant on the reef. Fish, for some reason, seem to leave
the large green fronds alone. Without the sea urchins, the algae simply take
over, growing everywhere and smothering the small coral colonies.
 
Sea urchins also play a vital role in helping corals to heal
wounds. Torn coral tissue can become infected with a blue-green alga. The tiny
algal threads grow in huge numbers forming a blue-green mat of fibers that spreads
over an infected coral head like a cancer. Such growths, perhaps over a period
of months, attack the living coral tissues until the whole colony is destroyed.
At night, the Diadema bristle forth
like an army of urban street cleaners. The urchins have hydraulically controlled
tube feet—several hundreds of them—tipped with suction cups. These carry the
spherical animals up vertical coral heads, along the roofs of caves, anywhere, in
their endless search for algae. Many times I've come upon a big black Diadema carefully eating away the infectious
blue green algae from small wounds on the coral reef. When urchins clean off
the area they do so completely, even removing the infected part of the coral skeleton.
 
There was, however, no obvious reason why one reef had
urchins and the other did not. We found many Bahamian reefs without urchins
and, on one of them, we planted a colony of Diadema to see if we could catch the urchin-eater at work. The black urchins fell to
work at once gobbling up the algae, but the next morning half of the population
of Diadema was gone. A few scattered spines
and bits of broken urchin plates were all that remained. Although we dived day
and night, we never managed to find out what was eating the urchins. Whatever
it was—probably a large fish—it did an efficient job; a week later there were
no more urchins on the experimental reef.
 
The problem, at least off Cape Eleuthera, did not seem to be
man-related, and it must have been going on for some time as the corals
themselves had altered their shape under the influence of the algal fronds.
Instead of forming rounded, domed colonies, many of the corals formed tall
pillars, being unable to grow out to the side because of the fringe of algae
that crowded in on them.
 
In Florida, I found a similar lack of Diadema on a similar algal-choked patch reef. Just south of the
famous Pennekamp State Park, Hen and Chickens Reef is a massive ruin compared
to what it was when I went to graduate school. As late as 1965 it was a healthy
reef with lush coral, fish, and invertebrate growth. Ten years later it was a
mess. Algae grew everywhere and the blue-green algal infection, so deadly to
corals, was evident on the few remaining live coral heads. There had been a
great deal of controversy over what killed Hen and Chickens. To me, the answer
seems obvious. The lack of Diadema,
usually very common on Florida patch reefs, had caused the reef to die in a
green tide of algae. But what caused the elimination of the sea urchins? And
what has kept them off the reef for ten years? We will come back to sea urchins
and patch reefs later, but now let us continue with reef "cells" of
another sort.”
 
I have always intuitively thought that the presence of Diadema at ecologically functional population
levels had a greater beneficial impact on coral reefs (control of coral disease
organisms and substrate conditioning) than just macro algae control. Doug’s
observations back in the late 70 seems to bear that out. Also the project that
Ken Nedimyer and I organized under the auspices of the FKNMS and with the
participation of NURC, showed that that not only can trans-located Diadema juveniles in densities of about
1 per square meter survive, they also have positive effects on the health of
patch reefs in the Florida Keys. NURC assessed the ecology of the four reefs in
the study, two experimental and two control, before the urchins were placed on
the reefs (08/31/01) and one year later (09/16/02) The results included an
increase in stony coral cover of 59% on the experimental reefs and a decrease
of 24.5% on the control reefs; juvenile coral density increased 151% on the
experimental reefs and increased 54.5% on the control reefs; crustose coralline
algae increased 159.5% on the experimental reefs and increased 0.5% on the
control reefs; brown foliose algae cover decreased 45% on the experimental
reefs and increased 31% on the control reefs. Publications on this project are available
on the FKNMS web site.
 
http://floridakeys.noaa.gov/research_monitoring/one_year_response.pdf
 
http://floridakeys.noaa.gov/research_monitoring/techniques_development.pdf
 
I may be naive, but I believe that Diadema in ecologically functional populations can be returned to our
coral reefs, at least to selected reef areas, though hatchery production of reef
competent juveniles and maintenance of ecologically functional populations
through artificial recruitment to take the place of natural recruitment until
effective reproduction of Diadema (one female can produce up to 15 to 20 million eggs at one spawn) returns to the
Caribbean. Adequate survival of settling Diadema and coral larvae seems to depend on the substrate conditioning activity of
adult Diadema. There are many
possibilities for returning Diadema to our coral reefs but a large supply of late larvae and early and older
juveniles must be available before such research can be developed.
 
Hatchery propagation of Diadema is difficult and this technology has not yet been completely developed. However
Tom Capo and the University of Miami, Dave Vaughan at the Mote Laboratory’s
Tropical Research Laboratory, and myself in a small home based laboratory have
all been successful in spawning and rearing Diadema.
I maintain a small brood stock under environmental controls and can
noninvasively spawn Diadema pretty
much on demand. I have also been able to rear and spawn the F2 generation. The
physical and nutritional elements of the culture have been developed, but water
quality seems to be a sticky problem. What remains to be accomplished is two
fold, success in production of surviving juveniles on almost every rearing run,
and production of large numbers, thousands of surviving juveniles on most
rearing runs.
 
Very limited funding, personnel, and facilities have thus
far been allocated to these efforts, and there are no other research efforts
currently in progress. Of course it is not possible to produce an iron clad guarantee
of success at any level of a Diadema restoration
process, but enough has been done with Diadema and Tripneustes (another genus of
ecologically and commercially valuable tropical sea urchin) to warrant confidence
that this can be done. It seems to me that the immense ecological and economic value
of healthy coral reefs to the tropical western Atlantic should stimulate an
effectively funded research effort into both propagation of these urchins and also
establishment of ecologically functional urchin populations on select coral
reefs. We can endlessly lament the decline of our Atlantic coral reefs, or we
can do something that has a chance to restore and preserve this unique and
valuable marine environment.
 
Martin Moe


On Wednesday, July 9, 2014 10:57 AM, "Szmant, Alina" <szmanta at uncw.edu> wrote:
 


Hi Peter:

I have not read this report yet, but I have heard from a couple of colleagues close to this issue that Jackson's downplaying of the role of climate change (and to be more precise, extreme warming events...aka global warming) in the Caribbean really ignores that major factors, the overriding factors, in Caribbean coral reef decline.  I think there is a critique of this report in prep by well recognized Caribbean coral reef scientists. While herbivory is obviously a critical process on coral reefs and I totally support protection of parrotfishes and other herbivores: common sense, looking around the Caribbean and the experimental study of Williams and Polunin (2001) show that there are not enough parrotfishes/herbivores out there to eat all the algae on a reef with less than 10 % cover.  Loss of parrotfishes did not cause bleaching and disease outbreaks.  Even major coastal development did not cause much coral mortality compared to the 1987, 1998, 2005
 bleaching events to list just a few of the most dramatic ones.  The Florida Keys has lots of parrotfishes (they are not preferred food for Americans) and there are plenty of algae in spite of huge herds of midnights, blues and acanthurids, as well as stoplights, red band and the smaller species.  

Human nature is not to bother until there is a crisis...the worse the crisis the more we respond.  We don't do much about "well this could be a problem in a few years.." which is why most coral reef 'management' and conservation efforts have failed...no urgency! In the case of coral reefs, the case for urgency has not been made well.  On the other hand, decisions about changing our global economy away from fossil fuels to renewables and to stop deforestation, and to slow and reverse human population growth/size, and to changes our patterns of consumption away from consumerism and meat eating will not be made because of our concern for coral reefs alone.  If you look around you (except for you Peter who live up in beautiful temperate forests), the natural terrestrial world is quickly disappearing to become part of the human footprint of urbanization and industrial agriculture.

Alina 



“Great minds discuss ideas; average minds discuss events; small minds discuss people.” Eleanor Roosevelt

“The time is always right to do what is right”  Martin Luther King

*************************************************************************
Dr. Alina M. Szmant
Professor of Marine Biology
AAUS Scientific Diving Lifetime Achievement Awardee
Center for Marine Science
University of North Carolina Wilmington
5600 Marvin Moss Ln
Wilmington NC 28409 USA
tel:  910-962-2362  fax: 910-962-2410  cell: 910-200-3913
http://people.uncw.edu/szmanta
*******************************************************


-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov [mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Peter Sale
Sent: Tuesday, July 08, 2014 3:49 PM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Caribbean reef decline, reality and fairy tales

Hi coral-listers,
In 2012, Roger Bradbury raised considerable ire amongst his coral reef 
buddies, by daring to paint a bleak picture of the state of the world so 
far as coral reef condition was concerned.  He used an Op-Ed in The New 
York Times to go contrary to the received wisdom that we must not tell 
people bad news because it only turns them off.  Far better to talk about 
the small glimpses of light: the rare MPA that works, the reef that 
mysteriously fails to bleach, the coral transplant project that seems to 
be replenishing reefs – to talk about them even if they are transient as 
well as small.  This helps people feel better about life, while we gently 
convince them that the sky really is, for the most part, falling.  (As you 
may have guessed, I don’t subscribe to this orthodoxy, although I do 
recognize that there are good ways and less effective ways of conveying 
bad news.)
As a recent example of this tendency to gloss reality with a glitter of 
false good news, consider the latest report on the state of the Caribbean 
(Jackson et al 2014).  We first heard about it also in 2012, when Jeremy 
Jackson presented some of the data at ICRS Cairns.  It is good to see IUCN 
has finally released it.
A careful read of this IUCN report provides abundant data, careful 
analyses, and sad conclusions on what has been happening to Caribbean 
reefs.  The science is well done.  The issue of loss of herbivory as a 
likely factor leading to the widespread massive overgrowth of macroalgae 
is appropriately reported, along with its cause – a disease that nearly 
wiped out Diadema antillarum across the region in 1983 (Lessios et al 
1984), and chronic overfishing which has decimated populations of 
herbivorous parrot fishes over most of the region.  Other important 
stressors, particularly the issues of too many tourists, coral diseases 
that were perhaps introduced in ballast water from outside the Caribbean, 
and various forms of pollution are also discussed.  Climate change turns 
out to have not yet had major impacts although those impacts are likely 
coming. 
The document also notes the absence of quality data and lack of uniform 
monitoring indices that make deciphering what has happened far more 
difficult than it should have been.  In my opinion, the authors fail to 
address the unfortunate lack of solid evidence for most of the causal 
processes inferred – if management interventions had been routinely, and 
appropriately monitored we would be far more certain of the links between 
overfishing, pollution, algal growth, coral recruitment and coral disease 
than we are.  Still, the authors do a generally responsible job of 
assessing competing hypotheses.  They also state, quite clearly that “the 
disparate reef histories clearly demonstrate the folly of attempting to 
understand the causes of coral reef decline for the entire Caribbean as a 
single ecosystem, an approach that ignores the enormous heterogeneity in 
environments and history of human and natural disturbance among different 
reef locations.”  With a careful read, this is a solid report, a 
publication I welcome.
But with a skim of the Executive Summary (the only part also available in 
Spanish or French), or a look at IUCN’s press release, or at various 
stories in the media from local Caribbean newspapers to Time Magazine, a 
rather different story emerges..  This one is far more about the value in 
protecting parrot fishes.. 
The Guardian’s headline is typical:  “Caribbean coral reefs ‘will be lost 
within 20 years’ without protection.  Major report warns that loss of 
grazing fish due to pollution and overfishing is a key driver of region’s 
coral decline.” 
IUCN’s own press release begins: “From despair to repair: Dramatic decline 
of Caribbean corals can be reversed.  With only about one-sixth of the 
original coral cover left, most Caribbean coral reefs may disappear in the 
next 20 years, primarily due to the loss of grazers in the region…” 
Whether the authors intended it or not (and I suspect they did not), a 
detailed, difficult, somewhat depressing tale, but with sound and 
constructive recommendations (including the protection of parrotfishes), 
has been morphed by IUCN and the media into an upbeat story about a 
Caribbean-wide serious problem which can be fixed by taking care of parrot 
fishes.  So much for the authors’ warning about the ‘folly’ of expecting a 
single, simple cause of coral decline across the Caribbean.
If all the ostensibly no-take MPAs across the Caribbean were functional, 
we'd have plenty of parrot fishes.  If just one decently scaled experiment 
that enhanced herbivory had been run, or if just one of the governmental 
decisions to protect parrot fishes was implemented with appropriate BACI 
monitoring so there would be data to evaluate, we might actually know if 
restoring herbivory will push the system back through the phase shift (not 
a given).  And, by the way, IUCN, you don't solve problems of coral 
disease or excessive tourism by protecting parrot fishes. 
Once again the simple and optimistic fairy tale has trumped telling the 
real story properly, and the world goes on spinning down while the science 
and conservation community looks on confused.  I KNOW we can do a lot 
better.
Maybe I am catching Gene Shinn’s ‘curmudgeon’ disease?
Peter Sale
University Professor Emeritus
University of Windsor
sale at uwindsor.ca                 @PeterSale3
www.uwindsor.ca/sale           www.petersalebooks.com



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