[Coral-List] Bleaching/disease at Flower Garden Banks
G.P. Schmahl
george.schmahl at noaa.gov
Tue Jan 10 14:20:53 EST 2006
This is an update on observations of the status of coral bleaching at
the coral reefs of the East and West Flower Garden Banks, northwestern
Gulf of Mexico. Coral bleaching is still present but much reduced
compared to surveys conducted in October and November 2005.
Surveys were conducted on January 3-4, 2006. A number of belt transects
were established, 15 meters long by 1 meter wide, in which every coral
colony was counted and scored as to its bleaching condition (totally
bleached, partially bleached or unbleached). Transects were established
from known reference points (mooring buoy anchor pins). The average
number of coral colonies affected by bleaching ranged from 4.5% (West
Flower Garden) and 10.3% (East Flower Garden). This is compared to an
average of 42% in October, and 46% in November. Of the species
affected, only Millepora alcicornis and Montastrea cavernosa had
colonies that were considered still "totally bleached" (1.3%), with most
species scored as "partially bleached". Only Millepora alcicornis
displayed mortality related to bleaching, but over 50% of the surveyed
colonies of that species contained areas of dead tissue. M. alcicornis
is not a dominant component of the living coral community, comprising
less than 2% of the total. Video was taken along each transect but has
not yet been analyzed. Water temperature during the survey was 74
degrees F (23 degrees C).
An observation of significant concern is an increased occurrence of
coral colonies displaying symptoms consistent with that of "white
plague" coral disease. In the previous bleaching surveys (October and
November) no disease was noted on the transects. During this survey,
slightly over 2% of the coral colonies within the transect displayed
white plague symptoms, and additional colonies were observed in the
vicinity. White plague symptoms were noted on Colpophyllia natans,
Diploria strigosa, Montastrea annularis, M. faveolata, and M. franksi.
Additional surveys will be conducted in the coming weeks to monitor the
status bleaching and disease.
--
George (G.P.) Schmahl
Sanctuary Manager
National Oceanic and Atmospheric Administration
Flower Garden Banks National Marine Sanctuary
1200 Briarcrest Dr., Suite 4000
Bryan, TX 77802
(979) 846-5942
(979) 846-5959 (fax)
george.schmahl at noaa.gov
http://flowergarden.noaa.gov
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