Is it true???

[Bernard THOMASSIN]

>Dear Alexander,

To answer to your question :

>"Is it true that "the 1997-98 El Nino killed 70% of all corals in the
>Indian Ocean"?"

I can assume that, for Mayotte Island (Comoro Archip.), located
in 
the middle of the north of the Mozambique Channel, observations 
before (April-June 1998) and following the establisment of the
"Coral 
Reef Observatory" (surveys in Dec. 1998, 1999, 2000), show that
on 
the outer barrier reef slope, about 80 percent and in place more
of 
the living corals between 3 and 15-20 m depth died following the
warm 
period of oceanic seawater bathing the island (mean weekly ocean 
seawater temperature >31°C and reaching 32°C). The genera more 
affected were : Pocilloporids, tabular and branched Acroporids, 
Diploastrea, massive Porites also bleached but partly recovered.
Bleaching occured during more 3 months (April to June 1998).
Even encrusting platy corals at 25-35 m deep were bleached in
June 98.
Even the soft corals (Sarcophyton cf. glaucum, Sinularia)
suffered 
and regressed in size.
As it was observed the coral communities living in fringing reefs
in 
coastal bays (more turbid and warm environments) less suffered
than 
corals living in clear waters on the outer slopes of the barrier
reef 
belt.

Huge bleaching also occured in Aldabra atoll (see Abstracts of
the 
ISRS 1998 Meeting at Perpignan).

People gave me observations from some of the Maldivian atolls. On
the 
slopes there, about 70-80 percent also of the coral coverage
died. I 
have some pictures.

If you have results from your enquiry from the West Indian Ocean 
coral reefs I ma interested for comparisons.

Cheers,

Bernard


Bernard A. THOMASSIN
Dir. recherches CNRS
Centre d'Océanologie de Marseille,
Station marine d'Endoume,
Chemin de la batterie des Lions,
13007 Marseille,
France
&
G.I.S. "LAG-MAY"
"Environnement marin & littoral de
l'île de Mayotte"
tél. (33) 04 91 04 16 17 (ligne directe)
     (33) 04 91 04 16 00 (standart)
mobile (33) 06 63 14 91 78
fax  (33) 04 91 04 16 35 (à l'attention de....)
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