[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


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