[Coral-List] Marshalls bleaching event & quarry pool recruitment

Dean Jacobson atolldino at yahoo.com
Fri Oct 27 22:37:01 EDT 2006

Hi listers:

In early October 2006 on Majuro atoll (RMI), shallow
coral bleaching was detected (the first episode since
last February), restricted to low-tide exposed
colonies (mainly Acropora, zooanthids)  Very low
mortality, so far. 
 More interesting, in mid-October, partial and total
bleaching was seen on massive Porites (cf.
lobata)colonies in the northern lagoon, in 2-4 m depth
(5 % of total population; 95% showed no signs of
Many tabulate Acropora and Millepora colonies were
partially or totally bleached as well.

An unrelated bit of news:

This semester I initiated a reef mapping class project
(with 4 coral ecology students) at the College of the
Marshall Islands.  A 5 year old, 100 meter long quarry
pool (max depth 6-7 meters) on the oceanside reef flat
of Majuro atoll (at the western end of the airport) is
currently recruiting corals and fish (with a dozen
coral species, mostly Pocillopora and Acropora, and 43
fish species, with only 3 butterflyfish spp, so far
established).   The pool has some sand substrate, but
having been blasted from hard cap rock, is dominated
by ideal rock substate for coral growth. 

 In a 30 year old blast quarry nearby coral cover is
very high, with over 70 fish species.

The longterm plan is to document changes in coral and
fish faunal composition over subsequent decades. 
Short term goals include to mapping, (using GPS),
labelling and photographing around 100 coral colonies
(max size is currently 15 cm or so).  Coral growth
rate (by area or height)will be quantified.  Algal
diversity and items of special interest, such as
location of cleaning stations (6 so far), will also be
noted.  The only conspicuous non-cnidarian invert is
the decorator urchin.

This site may also provide an opportunity to
transplant relatively (locally) rare favids and other
massive corals, to artificially increase diversity and
thus enhance this readily accessible site for teaching
and tourism purposes.  (I.e., it would be easier to
detect spawning in such a pool than in the often rough
conditions outside the reef flat)

I welcome comments and suggestions for other sampling
Dean Jacobson

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