Acropora White Syndromes
General Diagnostics: Lesions on elkhorn
coral (Acropora palmate) and staghorn coral (A. cervicornis) characterized by recent
tissue loss separating live tissue and algal-colonized skeleton; no evidence of
color change; absence of a pigmented band, no skeletal damage or abnormal growth.
Lesions may be focal, multifocal, coalescing, linear or annular. The lesion location,
shape and pattern of spread are unique for each syndrome. Snails or fireworms may
occur on lesions and they also cause similar patterns of tissue loss.
- White Band Disease (WBD) (A-E)
-
Lesions may be annular or linear, spreading from the base to the tips, or starting
at a branch bifurcation and spreading up or down; tissue loss advances 1-100 mm/day.
On A. palmata tissue loss may progress up the underside or upper surface
of the branch; the band also may encircle the entire branch. Tissue at the lesion
margin may be bleached (WBD type II) and small pieces of tissue may be peeling off
the skeleton (C) Exposed skeleton is progressively colonized by
epibionts.
- White Patch Disease (WPD) (F-I)
-
Also called patchy necrosis, white pox: Lesions are focal to multifocal, coalescing
lesions, irregular in shape, completely surrounded by living tissue. Lesions initiate
within a branch surface on unaffected tissue (I) or at the margin
of an old lesion (H) Colonies may have acute (recent), subacute
(colonized) and old lesions (F) lesions radiate out over time and
coalesce; resheeting occurs once mortality stops. Lesions have a sharply demarcated
leading edge of tissue loss; tissue remnants may be present and corallites may be
broken. 1- 80 cm in diameter, Damselfish may be associated with WPD lesions and
may cause similar patterns of tissue loss.
- Uncharacterized Rapid Tissue Loss (L,M)
-
White syndromes with diffuse, rapid tissue loss in an irregular pattern that differs
from WBD and WPD.
Similar Conditions
- Fireworm predation (J-K)
-
Resembles WBD type II; tissue loss confined to branch tips. Recent lesions lack
algal colonization; tissue margin is smooth and not sloughing.
- Snail predation(N)
-
Advances in a linear or annular pattern like WBD, but lesions have a serpiginous
scalloped or undulating margin the shape of the snail’s shell; snails are on the
lesion or at the colony perimeter.
- Damselfish bites (O-P)
-
Round to irregular, focal, multifocal or coalescing, small (1-3 cm) but expanding
lesions often with broken corallites; may form “chimneys”.
- Parrotfish predation (Q-R)
-
Irregular loss of tissue and underlying skeleton often at the edge of the branch;
scrape marks and jaw pattern may be visible.
View other
Biotic Diseases, or
Non-Biotic Diseases of the Western Atlantic.