Ten years after the crime: Lasting effects of damage from a cruise ship anchor on a coral reef in St. John, US Virgin Islands

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 lo ng and 3 m wide from a depth of 22 m to a depth of 6 m. The anchor pulveriz ed coral colonies and smashed part of the reef framework. In April 1991, ni ne permanent quadrats (I m(2)) were established inside the scar over a dept h 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 Agaric ia 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 re cruits settle into the scar in high densities, live coral cover has not inc reased significantly in the last 10 yrs, reflecting poor survival and growt h of newly settled corals. The relatively planar aspect of the scar may inc rease the vulnerability of the recruits to abrasion and mortality from shif ting sediments. Ten years after the anchor damage occurred, live coral cove r in the still-visible scar (mean = 2.6%, SID 2.7) remains well below the c over found in the adjacent, undamaged reef.