[Coral-List] Thermal stress and bleaching risk spreading in Caribbbean, parts of Pacific

Mark Eakin mark.eakin at noaa.gov
Thu Aug 21 15:06:53 EDT 2008

Northern hemisphere waters are continuing to rise and we are starting  
to receive reports of bleaching.  New graphics have been added with  
this week's update to the seasonal forecast.

A reminder of terms from the Coral Reef Watch satellite-based  
bleaching alert system:
Bleaching Watch: HotSpot values > 0
Bleaching Warning: HotSpot values > 1, currently accumulating thermal  
stress (Degree Heating Weeks)

Greater Caribbean:
Some warming has begun across much of the Caribbean and much of the  
Caribbean is now under bleaching watch.  This broad area of low level  
has been consistent with our new seasonal bleaching forecast.  We are  
now providing access to week-by-week images and animations from the  
forecast to help users better understand how the bleaching risk is  
likely to change through time.

18 of our 24 Caribbean virtual stations under Bleaching Watch, Lee  
Stocking Bahamas under Bleaching Warning and record high temperature:

Flower Garden Banks: Temperatures have cooled and the forecast models  
call for further cooling. Hopefully the threat will subside now that  
the sun and the greatest heating are heading south.

Florida: Slight cooling in Florida Bay and around the Keys will  
hopefully reduce the threat here as well.

Bahamas and Greater Antilles: The warming is moving in this direction  
and the forecast calls for continued warming for a few more weeks if  
we don't get some tropical storm cooling.  The satellite-based  
temperature of 31.2 degrees C is the highest we have seen this decade.

Lesser Antilles: The forecast calls for the greatest warming from the  
southern coasts of Hispanola and Puerto Rico, south and east through  
the Windward Islands to Trinidad.  At this point, all of these islands  
north of tobago are under a Bleaching Watch and further warming is  
expected.  Melissa Keyes reported seeing 5-10% paling around St. Croix  
this week.

Northern Coast of South America: The forecast calls for this area of  
greatest warming to include waters off the northern coast of Venezuela  
including Los Roques and the ABCs.  Much of this area is already under  
a Bleaching Watch.  The forecast still calls for further warming along  
the Colombian coast, much of which is already under a Bleaching Watch.

Central America to Mexico: The forecast models indicate that further  
warming will take place, primarily from Nicaragua to Panama.  This  
region has also warmed during the last week and much is under a  
Bleaching Watch.

Eastern Pacific
The seasonal outlook calls for very high temperatures and the  
potential for severe bleaching around the Baja Peninsula.  All of the  
southern half of the peninsula is under a Bleaching Watch or Bleaching  
Warning and continue to rise.

Central Pacific:
Bleaching Watch conditions have been reached at about half of the  
Northwestern Hawaiian Islands.  The forecast calls for further  
warming, especially at Midway and beyond, but it is not likely to be  

New virtual stations have just gone online for many of the Pacific  
islands and reefs at:

Western Pacific/East Asia:
Accumulation of thermal stress continues in earnest around Korea and   
southern Japan.  Keshavmurthy Shashank reported bleaching in  
Nishidomari, Otsuki worse than in 2007. DHW values have exceeded 4 off  
most of the main islands of Japan.  Thermal stress has begun along the  
Ryukyus, but temperatures have varied significantly along the chain --  
Okinawa has been under a Bleaching Watch, while temperatures at  
Ishigaki are back below the maximum monthly mean.  The forecast model  
suggests that this warming should subside in the coming weeks.  The  
forecast calls for the greatest warming in this region to be along the  
Northern Mariana Islands and Micronesia and down to Papua-New Guinea.   
The islands of FSM west of Chuuk and much of the region around Guam  
and CNMI are now under Bleaching Watch or close to the maximum monthly  
mean.  However, the forecast system does not call for severe bleaching  
in this area.

Our new seasonal bleaching outlooks can be found at:

Current HotSpot and Degree Heating Week charts and data formatted for
HDF and Google Earth can be found at:

Time series graphics for index sites can be found at:

You can sign up for automated bleaching alerts at:

Please report bleaching events (or non-events) at:

C. Mark Eakin, Ph.D.
Coordinator, NOAA Coral Reef Watch
National Oceanic and Atmospheric Administration
Center for Satellite Applications and Research
Satellite Oceanography & Climate Division
e-mail: mark.eakin at noaa.gov
url: coralreefwatch.noaa.gov

E/RA31, SSMC1, Room 5308
1335 East West Highway
Silver Spring, MD 20910-3226
301-713-2857 x109                   Fax: 301-713-3136

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