MEGANESIA - AN AQUARIUM OF
ENDLESS DIMENSIONS
A survey of the reef around the
break revealed a very different
reef than might be expected of
Australian or South Pacific reefs
of the central or western areas.
The coral diversity is low and
dominated by species which are
less abundant in the more
species-rich areas to the west.
The genus Pocillopora, with its
stubby, club-like branches, occurs
as numerous colonies over the
reef. It is a mound-like coral
that is less sharp than some of
the fast growing (Acropora) which
generally dominates reefs
elsewhere.
What the area lacks in diversity
is more than made up for with
coral cover (50% at the surf spot
and large areas of 80% to 100%
alongside the break). The fish
life is prolific with large
schools of parrot and surgeonfish.
Brightly coloured reef fish such
as butterfly fish are seen
throughout the area. |
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The general health of the reef is
good with no evidence of the
crown-of-thorns starfish, coral
bleaching, or the various coral
diseases. The prospect of the
terrestrial influences of
freshwater runoff and
sedimentation are minimal in the
atoll situation. This is because
the coral cays are composed
largely of fragments and coral
sand. Rain generally percolates
through the motu (island). In the
case of this spot, the currents
run at four knots. The tidal flow,
together with the wave action,
keeps this area very clean.
There has been a report of a
coral-bleaching event which
happened two years ago. In 1997,
there was substantial die-off of
some of the reefs, which coincides
with reports from Tahiti and
American Samoa during this period.
As part of the El Nino phenomenon,
a large pool of warm water
migrated east from the tropical
east Pacific. The elevated
temperatures in the coral reefs
surface waters (only 2°C will do
it), caused coral death among some
species. The dead-standing coral
that now makes up 25% in some
areas among some species. The
dead-standing coral that now makes
up 25% in some areas may be the
result of that incident.
What is particularly evident is
the process of motu or island
building. The motu’s beaches
surrounding the surf spot are
composed exclusively of coral
fragments. These are derived from
the coral growing on the reef
where pounding waves progressively
break the coral and wash the
pieces ashore. A dive over the
reef reveals colonies partly
broken due the weakened skeletons
caused by boring sponges or algae.
This occurs both in live and dead
coral. The organisms make their
homes in the skeleton by burrowing
into the branches. Too much of
this activity results in the
fracturing of the branch from wave
action or the parrot fish who
often browse the branch tips.
In summary, this is a magic reef
where the water clarity of 40
metres gives one the feeling of
swimming in an aquarium of endless
dimensions.
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