Is it true???
Bernard THOMASSIN
Bernard.Thomassin at com.univ-mrs.fr
Mon Jun 11 09:44:07 EDT 2001
>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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