Marshall Island Bleaching

Clive Wilkinson cwilkins at
Wed Sep 11 08:07:50 EDT 2002

>Date: Tue, 10 Sep 2002 17:23:07 -0700 (PDT)
>From: Dean Jacobson <atolldino at>
>Subject: Marshall Island Bleaching
>To: c.wilkinson at
>X-Scanned-By: MIMEDefang 2.6 (www dot roaringpenguin dot com slash
>I tried to submit a report to the NOAA website, but no
>joy.  Perhaps you could forward this report to any
>other interested parties.
>Coral bleaching, appears to have occured in Majuro,
>the capital of the Marshall Islands, for the first
>time.  This is of consern since the coral reefs here
>are very healthy (except where pollution is
>concentrated) and previously unaffected by bleaching.
>This event is restricted to a very shallow
>near-surface layer, and was first noticed on Sept 6
>(it probably appeared a few days earlier)following the
>observation of an unusually warm surface layer (only a
>meter or less deep)in the Majuro lagoon on Sept 4 (at
>which time no bleaching was yet observed). This
>surface water felt unconfrontably warm, almost hot, to
>an acclimated swimer.
>Later during the weekend I explored Majuro's SE ocean
>shore, and again found bleaching only of the most
>shallow corals (and intertidal zooanthids), along an 8
>mile stretch.  I would guess the entire atoll has
>experienced bleaching (the northern shore has not been
>sampled).  Local residents who were gleaning during
>the low tide report that they have never before
>witnessed this phenomenona.
>Much of the bleached coral emerged during the
>unusually low tides of Sept 9 and 10, but the
>bleaching clearly appears to have begun earlier, while
>completely emmersed.  We had very still, hot weather
>on Sept 1.  Further, the easterlies have been more
>active and consistant then the year earlier.  I
>suspect that a warm water mass was advected into our
>region during this event.
>Species affected include the uppermost intertidal
>Acropora (blue axial tips, A. seriata?) comingled with
>a rose-colored pocillopora, which also has bleached.
>Tip bleaching, marking the shallow thermocline below
>the shallow layer of warm water was found in Acropora
>nobilis and our large pale-margined Pocillopora sp.
>I am photo-documenting selected colonies at a site in
>my back yard (ocean side rock quarry pool), and will
>be monitoring their progress in coming weeks.
>Dean Jacobson, Ph.D., instructor of Marine Science at
>the College of the Marshall Islands and
>Board member of a new NGO: NCCMI, Nature Conservation
>Communities of the Marshall Islands.
>Yahoo! - We Remember
>9-11: A tribute to the more than 3,000 lives lost
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