[Coral-List] Coralline Algae Lethal Disease AKA Goreau's DiseaseAKA Algae White Disease
julian at tlfusa.com
Thu Nov 1 11:08:37 EDT 2007
Just a short observation.
I saw and photographed this happening in an aquarium. It formed the odd-looking "crop circle" pattern too! This appeared suddenly and was gone within a couple of weeks. The coralline algae resumed normal growth afterwards.
From: coral-list-bounces at coral.aoml.noaa.gov on behalf of Thomas Goreau
Sent: Wed 10/31/2007 5:16 PM
To: Aldo Croquer; Coral-list at coral.aoml.noaa.gov
Cc: Mark Littler; littlerd at gmail.com
Subject: [Coral-List] Coralline Algae Lethal Disease AKA Goreau's DiseaseAKA Algae White Disease
Dear Aldo and Coral List readers,
This slow spreading disease of encrusting red calcareous algae
expands in circular lesions, but often stops short of killing the
whole alga. It is distinguished by a white expanding ring, usually a
millimeter or two wide, but in some cases up to a centimeter wide,
with a sharp rim against the external pink or purplish encrusting red
calcareous alga, The interior of the expanding circle is made up of a
fine filamentous alga with a very distinctive olive green color.
I have documented it globally since 1991. I have many images on video
and a few photographs showing it all around the Caribbean, Indian
Ocean, Pacific, and South East Asia, but have never had the time to
compile them. However I have seen rare examples of it on much older
photographs, so while it is not genuinely a "new' disease, it has
certainly greatly expanded in the last 15 years.
I first noticed that this disease had spread very rapidly in the
intertidal sea level notch in Negril, Jamaica, over a few months
around 1991-2, and named it Coralline Algae Lethal Disease *CALD), by
analogy with the Littler's Coralline Lethal Orange Disease (CLOD).
Subsequently the encrusting reds in this habitat were overgrown and
killed by fleshy algae as the area became eutrophic and algae spread
all over the reef (NB: algae overgrew the reefs in Negril only in the
early 1990s, after tourism development and NOT after the Diadema die
off in 1983, or the earlier overfishing, as popular "phase shift"
mythology claims). Later Esther Peters mentioned it on her web site
and called it "Goreau's Disease", a name I 'd rather see confined to
something that is completely lethal and affects only politicians and
their scientific servants. CALD is what Ernesto Weil and yourself
have recently noticed and are now calling Algae White Disease.
I wrote a paper describing this around 1992 in a report on
environmental changes in western Jamaica published in the proceedings
of a conference held by the Negril Coral Reef Preservation Society. I
don't have either a xerox or a scanned copy available, and the
original is someplace in the mountain of boxes in my basement, that
is to say, effectively unreachable. It took me a couple of years to
convince Mark and Diane Littler that this was in fact a disease they
had not noticed before, and they now agree that it is far more
widespread than CLOD.
Since CALD is so widespread, and I don't have time to compile my
observations, I'm now forwarding this to the coral list server to see
if other people are also noticing it. I'm sure it is present almost
every place where encrusting red algae have not yet been totally
smothered by eutrophic fleshy algae, although it's frequency varies
greatly from site to site.
Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net
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