Mas Información:  Plaga Blanca

Friday, August 03, 2001 9:30 AM

Este mensaje lo envie ayer al grupo de discusion sobre
arrecifes de coral conocido como el Coral-List. A
continuacion, lo reproduzco para su conocimiento
general. Aunque el mismo esta redactado en ingles, les
dejo saber que trata sobre un nuevo brote de
enfermedades letales de corales en la Isla de Culebra.

En este caso, se trata de la enfermedad de la Banda
Blanca, la cual se observo ayer afectando 51% de las
colonias de Acropora cervicornis (coral cuerno de
ciervo), cuyas poblaciones, de por si, han disminuido
significativamente en muchas localidades del Caribe
debido al deterioro de la calidad del agua, huracanes,
enfermedades, colecciones para artesania, anclaje y
otras actividades humanas. A nuestro conocimiento,
este es el primer brote de dicha enfermedad durante el
2001 para el Caribe.

Ademas, en el mensaje se documentan algunos efectos
adicionales de la enfermedad de la cual les informe
previamente, la Plaga Blanca-Tipo II.  Asi mismo, se
documenta la presencia de colonias infectadas con la
enfermedad de la Banda Negra. Ademas, se documenta la
presencia de corales mostrando senales tempranas de
blanqueamiento en las especies Montastrea annularis y
Millepora alcicornis.  Finalmente, se documenta un
sindrome no observado previamente en una colonia de
Siderastrea siderea, el cual esta causando la muerte
de la misma.

Si alguien interesa mas informacion o tiene alguna
informacion que interesen compartir, pueden
comunicarse directamente conmigo.

Edwin

Hello,
I recently received a message about a virulent outbreak of plague type II in Puerto Rico, and that message has prompted this response to let folk know what we've seen and are doing here in St. John.  Researchers at Virgin Islands National Park (VINP) and the US Geological Survey field station in St. John, USVI have been monitoring the presence and progress of the coral disease plague type II in St. John on a monthly basis since December 1997.  (This work was recently presented in La Pagurea at the AMLC meeting, and a paper was submitted to Revista de Biologia Tropica as part of the proceedings to that meeting.)  We have observed the more typical occurrences of plague type II characterized by the sharp line differentiating apparently healthy tissue from diseased tissue.  In this form, the disease starts from the bottom of colonies, especially near sand or within depressions in corals (e.g., where sand and turf or macroalgae exist).  We have also observed virulent form of the disease in which mortality seems to progress much faster, cover a much larger area, and not necessarily start near the bottom of the colony.  This was observed in 1997 in a shallow (<10 feet) backreef environment, and also in 2000 on a reef slope (25-30 feet).  Both sites are located in undeveloped watersheds, one within the boundaries of VINP and the other outside the park.  The coral most commonly affected is Montastraea annularis (complex), although we've seen similar virulence in Colpophyllia natans  where the disease races through the colony.  The entire colony may be consumed or partial live coral may remain.  Currently, we have a list of 14 species being affected by plague type II: Montastraea annularis (complex), Montastraea cavernosa, Colpophyllia natans, Siderastrea siderea, Dendrogyra cylindrus, Mycetophyllia lamarckiana, Agaricia agaricites, Eusmilia fastigiata, Madracis mirabilis, Madracis decactis, Porites porites, Porites astreoides, Leptoseris cucullata, and Stephanocoenia michelinii.  Tissue samples were taken from five species for lab analysis which verified the disease pathogen.  We have also observed plague type II in the British Virgin Islands, and on Buck Island, off the island of St. Croix.

In consultation with Dr. Laurie Richardson, we have conducted some in situ experiments to "smother" this aerobic bacteria by applying a two part epoxy to the margin between the apparently healthy and diseased tissue (extending about an inch into both sides).  The disease line stopped advancing in 3 of 4 cases, but given the sporadic nature of the disease response, it is impossible to say whether the epoxy had any affect.  (We plan to conduct more experiments along these lines.)

Feel free to share this with anyone that might be interested, and I can be contacted by return e-mail or at 340-693-8950, ext 227.

All the best,

Jeff Miller
 

Photo legends:

1) plague II, 1997: photos of rapid, extensive mortality in 1997
2) plague II, 2000a: initial outbreak of rapid, extensive mortality in 2000.  Yellow dot marks "horseshoe-shaped" lobe for reference.
3) plague II, 2000b: six week post 2000a photo.  Yellow dot for reference.  Dotted, yellow box denotes the approximate boundaries of the 2000a photo.  White quadrat is 1 meter².
4) plague II, epoxy not working: Mortality progressed beyond the epoxy on C. natans.
5) plague II, epoxy working: Mortality contained within epoxy boundary on C. natans.
 

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