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Abstract
Rogers,
C. S. and Garrison, V. H. "Ten years
after the crime: lasting effects
of damage from a cruise ship anchor on a coral reef in St. John,Virgin
Islands,"
Bulletin
of Marine Science,
2001, 69:2,
793-803
Abstract:
In October
1988, a cruise ship dropped its anchor on a coral reef in Virgin
Islands
National Park
St.
John,
creating a distinct scar roughly 128 m long and 3 m wide from a depth
of 22 m
to a depth of 6 m. The anchor pulverized coral colonies and smashed
part of the
reef framework. In April 1991, nine permanent quadrats
(1 m2) were established inside the scar over a depth range of 9 m to
12.5 m. At
that time, average coral cover inside the scar was less than 1%. These
quadrats were surveyed again in 1992, 1993,
1994, 1995 and
1998. Recruits of 19 coral species have been observed, with Agaricia
agaricites and Porites
spp. the most abundant. Quadrats
surveyed outside the scar in June 1994 over the same depth range had a
higher
percent coral cover (mean=7.4%, SD=4.5) and greater average size
(maximum
length) of coral colonies than in quadrats
inside the
damaged area. Although
coral
recruits settle into the scar in high densities, live coral cover has
not
increased significantly in the last 10 yrs, reflecting poor survival
and growth
of newly settled corals. The relatively planar aspect of the scar may
increase
the vulnerability of the recruits to abrasion and mortality from
shifting
sediments. Ten years after the anchor damage occurred, live coral cover
in the
still-visible scar (mean=2.6%, SD=2.7) remains well below the cover
found in
the adjacent, undamaged reef.
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