CORDIO Status Report 1999.pdf

BLEACHING EVENT
SST anomaly data indicate that Socotra was affected by
increasing temperatures from 12/5/98 to 30/5/98. A
0.5°C rise off Somalia 14/4/98 reached the western tip of
Socotra 17/4/98, and surrounded Socotra by 28/4/98.
Warmer waters (1°C rise) developed off the South
Yemen coast around 2/5/98 and a large warm water
mass (+ 1–2°C) developed off the north coast of Socotra
from 12/5/98. This mass enveloped Socotra and the
south coast of Yemen and Oman by 19/5/98. From 23/5/
98 to 26/5/98, it spread from the bottom of the Red Sea
to the Gulf, bordering the north coast of Socotra.
Cooling began 30/5/98, to less than 1°C, and no anomaly
occured after 9/6/98.
EFFECTS ON CORAL REEFS
Corals were reported to be alive in March 1996 (Kemp,
M.E.P.). Bleaching was first observed in mid to late May
1998 by De Vantier. Post-bleaching, dead coral was
observed in November 1998 (Turner, Klaus, Simoes &
De Vantier). By March/April 1999, coral, especially
branching Acropora washed up on beaches as high
berms after storms (Simoes). In April 1999, unbleached
live coral was found around the Brothers (Abd el Kuri)
(Krupp, 1999), and in deeper water off the north coast of
Socotra (> 10 m) (Zajonz, 1999).
In November 1998, Turner, Klaus, Simoes and De
Vantier found that 99% of the tabular, branching and
massive corals surrounding Socotra were dead. Small
faviids, at > 7 m depth, were mostly unaffected. Many
soft corals, especially Sinularia, were bleached but alive.
The coral structure was still standing in most places,
and was still used as habitat by fish, though covered in
filamentous algae. Areas of mobile coral rubble were
developing. Of the Brothers, only Darsha and Semha
were surveyed. Surprisingly, they were barely affected
by bleaching.
In March to April 1999, another survey was carried
out by Simoes, Krupp and Zajonz. They found that
storms had caused breakage of branched corals, which
were then swept up onto the beaches.
SOCIO-ECONOMIC EFFECTS
In November 1998, it was suggested that storms during
the monsoon would probably cause break-up of the
coral structure. This had happened by March 1999.
Fisheries will be severely effected – the lobster
fishery may decline, and the fishermen may need to
turn to deep-sea fishing. A decline in fisheries could
cause poor protein diet and even greater poverty.
No further erosion effects are expected, due to the
already severe exposure.
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