Coral communities and environmental parameters were surveyed at 6 sites around Brampton Island in February 1995. Study sites were established at Brampton Roads (Sites 1a, 1b), Turtle Bay (Site 2), Dinghy Bay (Site 3), Western Bay (Site 4), Osprey Point (Site 5) and Pelican Island (Site 6).
The overall status of coral communities in the area was assessed using semi-quantitative surveys, consisting of 20-30 minute SCUBA-swims on the shallow reef slopes at each site. A comprehensive list of the sessile benthic taxa, identified in situ to genus and species for hard corals, genus or species for most soft corals and macro-algae, and to higher taxonomic rank for other benthos was compiled. Each taxon was ranked subjectively in terms of its relative abundance and the approximate proportion of coral colonies that were in each of three size classes. The approximate proportion of colonies that had sustained substantial injury to >50% of colony surface area was estimated. In addition, visual estimates of the approximate percent cover of the overall substrate at each site attributed to major biotic and abiotic benthos were made.
Quantitative surveys were conducted at three sites to determine the percent cover, size structures and levels of injury of the coral communities as well as the abundance of macro-algae. At Brampton Roads, sites were surveyed in the impacted area, in the vicinity of the Snorkel Adventure Trail (SAT) (Site 1a) and near the opposite end of the patch reef (Site 1b). Site 6, near the south-western corner of Pelican Island was used as a control.
Video transects were used to estimate percent cover. At each site, five haphazardly placed, 50 m long video belt-transects were filmed by a diver swimming at a near constant-speed and set-height above the substratum. The resulting video-transect width ranged from about 30-50 cm of reef substrate.
Three 32 m x 0.6 m belt-transects were surveyed at each of the three sites (on video transects 1, 3 and 5 at Sites 1a, 1b and 6). The sessile benthos located within each transect were recorded to species or genus and growth-form for hard corals, genus for most soft corals and zoanthids, and order or higher taxonomic rank for other sessile benthos. The maximum diameter of each organism (to the nearest cm for organisms < 50 cm diameter, and to the nearest 5 cm for larger organisms) was recorded. For hard corals, the approximate proportion of the colony that was dead, to the nearest 10% of colony surface area, was estimated.
Water and sediment samples were collected for nutrient analysis from all sites except for Brampton Roads Site 1b. At Brampton Roads (Site 1a) and Pelican Island (Site 6) duplicate water, sediment, as well as algal (Sargassum and Padina) samples were collected at three points on three of the five transects established at each reef. At these two sites, one of the replicate sediment samples was used for nutrient analysis and the duplicate used for sediment grain size analysis. At sites 2, 3, 4 and 5 duplicate water and sediment samples were taken at each of 3 points approximately 50 m apart.
The spatial distribution of dissolved nutrients between the resort and the Brampton Roads reef was also measured using a series of 5, parallel 50 m transects in the bay between the beach and the reef. This sandy bottom area lies between the potable water dam adjacent to the airstrip, and the sandspit at the north end of the resort. Duplicate water and sediment samples were taken at three randomly located points on each transect and transects were spaced about 50 m apart. At the southeastern end of this area, the small stream of water running from the base of the potable water dam during low tides was sampled for dissolved nutrients at three points along the stream (low tide level, halfway and at the base of the dam) taking duplicate samples on 23 February and a single sample on the following day.
