Epyzzotic problem on Acroporas in P. Rico.

EWeil eweil at caribe.net
Mon Dec 10 12:23:16 EST 2001

Dear Colleagues,=20

In the last three weeks almost all stands of Acropora palmata in the =
southwestern area of Puerto Rico (Guanica to Parguera) have been =
affected by a syndrome that fits patchy necrosis (described by Andy =
Bruckner) etiology. The colonies show white-dead amorphous areas all =
over the top surface (not round-like tipical of white pox) and branch =
tips (see pictures). Some colonies show extensive mortality while others
only the small dead spots which become colonized rapidly by filamentus =
green algae and do not seem to advance and kill more tissue. Other =
blotches seem to advance very quickly with the tissue peeling off the =
coral skeleton. Some of these necrotic areas are being produced by fish
faeces (surgeon and parrot fish). The faces are compact and dense and =
stick to the coral surface if water movement is restricted. =
Coincidentaly, we have had an unusual calm weather (no wind, no waves, =
very slow currents) on this side of the island for at least 12 days wich
favors a longer than normal permanence of the feaces in contact with the
live surface. If you remove the feaces, the underneath coral tissue is =
dead. Nevertheless, the extension of the problem (several reef areas =
over more than 20 km) and the characteristics of other necrotic areas =
(to extensive to be explained by this factor) makes us suspect that a =
pathogen is involved here. Our first estimates from four reef areas with
dense popualtions of A. palmata indicate that between 56 and 74 % of all
colonies (with almost all of the large colonies included here) are =
affected by this problem.  We have tagged several colonies which will be
checked routinely. Some colonies show partial recovery over dead areas.

Has anyone seen anything like this in his/her areas of research??
Please contact me if you've seen some thing similar.


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