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Hurricane Hugo (1989) severely damaged the framebuilding coral Montastrea annularis on the shallow reefs in Greater Lameshur Bay, St. John. Before the storm these reefs were dominated by M. annularis and a permanent study area was established at 10 m depth to monitor changes in abundance of this species. The storm destroyed, on average, > 33 % of the live cover of M. annularis in the study area. Post-hurricane reefs contained numerous detached colonies in piles or packed into cavities within the reef framework, large areas of vacant hard substratum and extensive growths of the red algae Ljagora spp. Video transects (80 m*) at the same depth and on either side of the study area showed that this damage was patchy. Although these reefs may remain dominated by M. annularis it is possible that the scleractinian fauna will change as a result of colonization by other coral species and delayed mortality of detached M. annularis colonies. Hurricanes regularly impact Caribbean regions (e.g. Glynn et al. 1964, Stoddart 1985) causing severe damage to terrestrial and marine communities. Sustained wind speeds can exceed 120 km h-' and may gust to more than 300 km h-', while hurricane waves have been recorded as high as 23.6 m (Stoddart 1985). The most comprehensive description of hurricane effects on coral reefs is for Discovery Bay, Jamaica, where baseline data were available for more than 2 decades before Hurricane Allen hit the island in 1980 (Woodley et al. 1981). Hurricane Allen severely affected bot'h sessile and mobile fauna on Jamaican reefs, although the effect was patchy and showed variation among coral species. The planar area of branching corals such as Acropora cervicornis was reduced by up to 99 % but massive colonies such as Montastrea annularis lost only 9 % of their area at 6 m depth (Woodley et al. 1981). More ' Present address and reprint requests: University of Southern California, Catalina Marine Science Center, PO Box 398, Avalon, California 90704, USA O Inter-Research/Pnnted in Germany extensive damage to M. annularis occurred at 10 m depth, where up to 65 % of the massive head corals (brain corals and M. annularis pooled) were toppled. Catastrophic damage to delicate corals and the survival of robust massive colonies is common during major storms (Rogers et al. 1982, Stoddart 1985, Kjerve et al. 1986) and has important implications because massive corals build the framework of coral reefs (Sheppard 1982). On 18 September 1989, Hurricane Hugo passed ca 56 km to the south of St. John, US Virgin Islands, with sustained winds of 225 km h' and gusts of 320 km h-' (Climate Analysis Center 1989). Greater Lameshur Bay (GLB) has a southerly aspect and an axis perpendicular to the storm and, therefore, was exposed to the full force of the hurricane waves. In 1987 permanent study sites had been established in GLB to monitor changes in abundance of the primary framework coral Montastrea annularis which dominated the shallow reefs (10 m depth) of GLB (Edmunds et al. 1990) with columnar-lobate colonies. These areas provided the opportunity to determine the effect of Hurricane Hugo on the reef framework and this note describes the results of our quantitative analyses. Methods. The study site is at 10 m depth off the tip of Yawzi Point in GLB and consists of adjacent quadrats (n = 10, each 0.75 m2) along each of three 10 m long transect lines (total of 30 quadrats) which are parallel to one another and are permanently marked. Quadrats were photographed in April 1989 and 6 wk after Hurricane Hugo (Nikonos V, 28 mm lens). Projected color slides were overlaid with a grid of 200 randomly spaced dots to determine percent cover of Montastrea annularis, the red algae Liagora spp. (mostly L. rnucosa) and free space (hard substrata: rock and coral rock) from the proportion of dots on each substratum. M. annularis was the only coral quantified in these Mar. Ecol. Prog. Ser. 78: 201-204, 1991 areas because it formed a virtual monospecific stand and the photoquadrats required to measure colonies (> 1 m diameter) of this species did not have sufficient resolution to detect other, less abundant, scleractinians (Edmunds et al. 1990). Sand substratum was not quantified because coral planulae larvae will only settle on solid substrata (Fadlallah 1983). Many of the columnar-lobate colonies of Montastrea annularis were broken into individual lobes by Hurricane Hugo but this type of damage was not accurately quantified with surface area determinations. Therefore, in each slide we counted the M. annularis lobes that were detached from the substratum and expressed them as a percent of the total lobes present. To increase the area of our post-hurricane surveys, four 20 m long band transects were filmed at the same depth as the permanent quadrats using a hand-held high resolution Sony V9gTM video camera aimed vertically downward. Band transects were perpendicu.lar to the end.s of the 2 outer, permanently marked transect lines. Sequential, non-overlapping fields of view (each 1.0 m2) were freeze-framed on a color monitor and substrata areas determined using a grid of 200 randomly spaced dots as described above. To determine the size of the living tissue remaining on fragments, detached lobes were selected at random from the video and the outlines of their living tissue were traced onto plastic sheets. The planar area of the live tissue was then measured by digitizing the individual outlines. All percent cover data were arcsine-transformed before analysis (Sokal & Rohlf 1981) and were compared between times with a Student t-test. Results. Hurricane Hugo resulted in significant changes to the primary framework coral in GLB. Some of the colonies used as reference points for the study area were completely destroyed and we were unable to relocate 12 of the quadrats. Thus, the estimate of reef destruction is conservative because it does not incl.ude these 12 quadrats with extensive coral damage. There were significant changes in substratum composition as a result of Hurricane Hugo (Fig. 1). Mean percent cover of Montastreir annularis decreased b y 34 % (42 % to 28 %; t = 2.048, df = 46, p < 0.05), detach.ed lobes of M. annularis increased by 13-fold (2 9'0 to 25 'h; t = 3 271, df = 46, p < 0.01) and free space Increased by 82 % (15 % to 27 %; t = 3.311, df = 46, p 0.01). The cover of Liagora spp. increased ( t = 5.722, df = 46, p < 0.001) from 0 % to l l ':L, and inspection of the color slides showed that most of the Liagora spp. were not growing on living M. annulans but on add;tional free space created by the storm. This suggests that Hurricane Hugo resulted in a 153 % increase In free space as determined from the sum of the space occupied by Liagora spp. and the free space (Fig. 1). 70 A Before Hugo

Effect of Hurricane Hugo on the primary framework of a reef along the south shore of St. John, US Virgin Islands