[Coral-List] Bleaching update in PRico

EWeil eweil at caribe.net
Wed Nov 5 13:27:50 EST 2003

Dear Colleagues, 

Following this morning posting by Gang Lieu about the thermal stress in PR "With anomalously high sea surface temperatures (SSTs) developing over most of the Caribbean Sea since late August the SST at Puerto Rico has maintained above the summertime maximum monthly mean SST since August and around the level of bleaching threshold since late September.

Our satellite monitoring shows that the thermal stress is still lingering around the bleaching threshold at Puerto Rico. Accumulated thermal stress at Puerto Rico has now reached a level of 3.7 Degree Heating Weeks. 
Mild bleaching has been observed at some locations in the area since September. If the area experiences a sustained thermal stress for any longer period of time, widespread bleaching may be expected. However, at
a time this late in the season, any new bleaching event is not expected to last long".

Our latest observations indicate that what started as a mild bleaching event in late Sep - Oct, turned into a intensive, widespread bleaching event. The most intense and widespread bleaching wwith the highest number of species is happening above 10-12 m deep. Deep communities (below 15 m) show a few colonies bleached only. However, as mentioned in my last communication, an epizootic event of white plague that started in mid sept is now spread out through most reefs in the shelf edge (>18 m) with many species affected and colonies dying at prety fast rates. 
We are compiling informatioon and data on the number of species affected by both bleaching and WP,  the proportion of colonies within each species, rates of mortality, etc in several reefs. We are also following several tagged colonies as well. No mortality dure to bleaching has been observed yet. The intensity and extension of the bleaching so far is  somehow lower than our last event in 1998, when several large and mediun size colonies of Montastraea and Diploria completely bleached and the event affected deep and shallow communities alike.

More to come in the near future!


Ernesto Weil, Ph.D
Department of Marine Sciences
University of Puerto Rico
PO Box 908
Lajas PR 00667
Pho: (787) 899-2048 x. 241/272
Fax: (787) 899-5500 

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