[Coral-List] Coral diseases and algae

[Thomas Goreau]

Dear Gene,

The chronology you propose below does not match our field  
observations, at least in Jamaica. The Acroporas all along the North  
Coast of Jamaica were pretty much intact until Hurricane Allen in  
1979, which devastated them, and from which they never recovered  
because Coralliophila snails ate the surviving fragments (Judy Lang  
followed that). 1979 was also the year that White Plague first was  
reported by Bill Gladfelter devastating the USVI, although Arnfried  
Antonius had clearly documented it a year earlier in Vieques. WB seems  
to have raced through the eastern Caribbean slightly earlier. But we  
never saw it have a serious impact on Acropora in Jamaica because the  
hurricanes got them first. There was no recovery of Acropora in  
Jamaica after the Diadema mass mortality in 1983, but from time to  
time northers would clear off the algae on ridges that focused wave  
energy and a few Acroporas managed to settle on these few favored  
spots before the algae grew back, but they were inevitably wiped out  
by bleaching, algae, or white band disease later. Claims of a  
"recovery" of Acropora near Discovery Bay are erroneous, the entire  
"recovered" population died from bleaching before the "recovery" paper  
was even published. The eutrophication of Jamaican reefs took place  
over a 40 year period, following local population growth in each area.  
In Discovery Bay it took place starting in the early 1980s, before the  
Diadema die off. Other areas went in the 1950s, 1960s, 1970s, and the  
last areas to have the coastlines developed did not go until the  
1990s. The chronology of the coral to algae shift in Jamaica had  
nothing to do with either overfishing or Diadema, despite considerable  
popular mythology on the subject, and is described in T. J. Goreau,  
1992, Bleaching and reef community change in Jamaica: 1951-1991, in  
SYMPOSIUM ON LONG TERM DYNAMICS OF CORAL REEFS, AMERICAN ZOOLOGIST,  
32: 683-695

Best wishes,
Tom

On Feb 23, 2009, at 10:20 AM, Eugene Shinn wrote:

> Tom, I question whether it was eutrophication..the recovering  
> acroporids died right after the Diadema died and the algae and  
> disease took over. It was after the big hurricane...Forget if it was  
> 1983 or 84.. The two years of maximum dust transport from Africa  
> when Diadema, seafans, and acropora croaked everywhere in the  
> Caribbean.
>
>> Dear Gene,
>>
>> When I first began photographing YBD in Jamaica in 1987 we thought  
>> it was delayed recovery from bleaching, and it took Craig Quirolo  
>> five years to convince me it was a disease. Discovery Bay nutrients  
>> reached eutrophic levels in the early 1980s, long after overfishing  
>> had taken its toll, and the corals were being overgrown with  
>> algae.  On those corals that were part of my long term coral growth  
>> monitoring study, I would systematically weed back any algae that  
>> could overgrow the corals, and it made no difference to the corals  
>> with YBD, just as the new paper suggests.
>>
>> By the way the effect of overfishing in Jamaica was not to  
>> eliminate herbivorous fish, as top-down dogmatists would have us  
>> believe, but precisely the opposite. In the early 1950s the reef  
>> was dominated by predatory and invertebrate eating fish, and there  
>> were very few herbivorous fish. After overfishing and coastal  
>> eutrophication the fish population switched to overwhelmingly  
>> herbivorous species, because that is all the food there is now. So  
>> the problem is not lack of grazers at all, but that the over- 
>> fertilized algae grows so fast that no grazers can control them.
>>
>> However I am not sure this lack of obvious algae interaction  
>> applies to other coral diseases than YBD. Jennifer Smith and  
>> colleagues, and Maggie Nugues and colleagues, have made convincing  
>> cases for possible interactions of coral disease pathogens and  
>> algae based on lab experiments and small scale field associations.  
>> We found very strong associations between many diseases and certain  
>> algae quite unexpectedly from data analysis of large scale studies  
>> of coral reef health in the Turks and Caicos Islands. All the coral  
>> diseases that were abundant enough to be tabulated at all sites  
>> (White Plague, Black Band Disease, Gorgonian Disease) were  
>> significantly associated with at least one algae genus. However YBD  
>> was too rare there to tabulate........
>>
>> For the detailed non-parametric statistical correlations based on  
>> extensive ecological assessment of 26 ecological and environmental  
>> parameters at 47 sites, including those between algae and coral  
>> diseases, see the first paper and appendices at:
>> http://globalcoral.org/Turks and Caicos Islands Coral Reef Health  
>> Assessment.htm
>>
>> Best wishes,
>> Tom
>>
>> Thomas J. Goreau, PhD
>> President, Global Coral Reef Alliance
>> Coordinator, United Nations Commission on Sustainable Development  
>> Partnership in New Technologies for Small Island Developing States
>> 37 Pleasant Street, Cambridge MA 02139
>> 617-864-4226
>> goreau at bestweb.net
>> http://www.globalcoral.org
>>
>>> Date: Fri, 20 Feb 2009 09:53:51 -0500
>>> From: Eugene Shinn <eshinn at marine.usf.edu>
>>> Subject: [Coral-List] Do corals need fish to remain healthy?
>>> To: coral-list at coral.aoml.noaa.gov
>>> Message-ID: <a0623090bc5c34a2c6813@[131.247.137.127]>
>>> Content-Type: text/plain; charset="us-ascii" ; format="flowed"
>>>
>>> The Program Manager at the Florida Keys National Marine
>>> Sanctuary  recently made me aware of a new paper titled, "Macroalgae
>>> Has No Effect on the Severity and Dynamics of Caribbean Yellow Band
>>> Disease." Ivana Vu et. al, 2009, published in PloS Feb 09 Vol 4  
>>> Issue
>>> 2. The paper is the result of an ingenious  manipulative field study
>>> in Puerto Rico. As the title implies it shows, that various
>>> Macroalgae have no effect on CYBD in Montastraea faveolata . This
>>> conclusion contradicts the widely repeated mantra that these algae
>>> stimulate coral disease by serving as a reservoirs of pathogens  and
>>> that their proliferation on reefs is due to removal of herbivorous
>>> fishes. In other words, remove fish (overfishing) that eat algae and
>>> the algae will grow and cause decline of coral.
>>> When I read the paper I was reminded of a recent conversation with
>>> Harold Hudson of Reef Tech  who described to me what he recently saw
>>> in Roatan. "It was the biggest healthiest staghorn coral forest I
>>> have seen in many years", he said.  What caught his eye also was  
>>> that
>>> there were essentially no fish! Not even the ubiquitous Damsel fish
>>> that normally thrive among staghorn branches. It was wonderful to
>>> hear that such healthy staghorn fields still exist but isn't it odd
>>> that it is thriving  without the usual tropicals, surgeon, and  
>>> parrot
>>> fish? Similar observations have been recorded by J. Keck et al.,
>>> "Unexpectedly high cover of Acropora cervicornis on offshore reefs  
>>> in
>>> Rotan (Honduras)" published in Coral Reefs, DOI
>>> 10.1007/s00338-005-0502-6  and also confirmed in a paper by B. Riegl
>>> et al, Offshore refuge and metapopulation resilience explains high
>>> local densisty of an endangered coral (Acropora cervicornis). In
>>> Marine Pollution Bulletin.  Many of us can remember the luxurious
>>> corals on the North coast of Jamaica before the early 1980s at a  
>>> time
>>> when the area had already been fished out. Apparently what ever
>>> started the general Caribbean decline in the late 1970s and early
>>> 1980s remains  somewhat elusive but widespread.  I suggest we need
>>> more straight-forward in-the-field experiments such as the Puerto
>>> Rico study cited at the beginning.  May be we should  rethink the
>>> commonly cited association between fishing and coral health??  Gene
>>> --
>>>
>>>
>>> No Rocks, No Water, No Ecosystem (EAS)
>>> ------------------------------------  
>>> -----------------------------------
>>> E. A. Shinn, Courtesy Professor
>>> University of South Florida
>>> Marine Science Center (room 204)
>>> 140 Seventh Avenue South
>>> St. Petersburg, FL 33701
>>> <eshinn at marine.usf.edu>
>>> Tel 727 553-1158----------------------------------
>>> -----------------------------------
>
>
> -- 
>
>
> No Rocks, No Water, No Ecosystem (EAS)
> ------------------------------------  
> -----------------------------------
> E. A. Shinn, Courtesy Professor
> University of South Florida
> Marine Science Center (room 204)
> 140 Seventh Avenue South
> St. Petersburg, FL 33701
> <eshinn at marine.usf.edu>
> Tel 727 553-1158----------------------------------  
> -----------------------------------<genes coral dust (GRL) pdf.pdf>

Thomas J. Goreau, PhD
President, Global Coral Reef Alliance
Coordinator, United Nations Commission on Sustainable Development  
Partnership in New Technologies for Small Island Developing States
37 Pleasant Street, Cambridge MA 02139
617-864-4226
goreau at bestweb.net
http://www.globalcoral.org