More Coral Bleaching in Hawaii

Steve Coles slcoles at
Fri Sep 20 15:44:46 EDT 1996

Yesterday (19Sep96) I observed moderate coral bleaching on the reefs of 
leewad Oahu, Hawaii from Nanakuli to Kahe Point and to depths of 8 m.  From 
these observations, it can be assumed that this condition extends to the 
entire western side of Oahu, the first time that it has been reported from 
this area.  In contrast to the total zooxanthellar pigment loss reported 
last week for corals in two areas in embayments on windward Oahu, the 
present bleaching is partial and limited to three species.  Pocillopora 
meandrina is most affected, with about 5% of the colonies observed having 
lost pigmant on their branches but retaining some zooxanthellar pigment in 
their branch bases, resulting in a pale coral with the pink to rose coral 
characteristic of coral tissue pigments.  Encrusting Montipora capitata 
(=verrucosa), present in low abundandance, is totally bleached, while 
encrusting Montipora patula ranges bleached to normal.  The dominant coral 
in the area, Porites lobata, with a few exceptions, is generally unchanged. 

This is the first time this phenomenon has been observed in this area in 25 
years of monitoring.  This is a completely open coastline with no 
opportunity for restriction of circulation that would promote localized 
heating of ambient water. Temperature measured at the time was 27.0-27.2 
deg. C. Intake temperatures continuously monitored by the nearby Kahe Power 
Station will provide a record for the last month which can be correlated 
with this event. 

More information about the Coral-list-old mailing list