Yet another bleaching note

[Judith C. Lang]

For those who haven't yet already heard: 
Mass bleaching (once again) has occurred around Lee Stocking Island, Exuma 
Cays on the eastern margin of Great Bahama Bank, in the central 
Bahamas---in response, we suspect, to a brief warming period during the 
second half of September.  Affected corals have been seen to depths of 
about 40m, but not at "submersible depths" (60 to 90 m) on the deep fore 
reef. 

As in previous events (1987, 1990, 1993), reef corals on a shallow (4 - 6 
m), leeward patch reef (Rainbow Gardens) were affected more severely than 
conspecifics at a nearby, shallow (3m), exposed fore reef (Normans fringing 
reef--S end).  Ambient flow is strong after high tides at Rainbow Gardens, 
while the reverse is true at Normans.  We have previously suggested (Lang, 
Lauderdale, Crawford, Dennis, Wicklund and Hayes, unpubl. Abstract) that 
the Rainbow Gardens reef is more susceptible to bleaching because it's 
relatively more exposed to the warm, saline underflows that move off the 
Bank at low tides during the summer and early autumn.  There's a 
thermograph on each reef, and the data have been downloaded but aren't yet 
analyzed, 

Judy Lang, with thanks to Ouida Meier, George Dennis, Shelley Anthony and 
Heinz Proft.