Barcadera Reef Both Bonaire and Klein Bonaire are surrounded by continuous, fringing coral reefs from the shoreline seaward to depths in excess of 70 m, covering an area of some 2,600 ha. Reef formation begins at the shoreline with a gradually shelving submarine terrace extending seaward by up to 250 m. Beyond this, at depths of 10-12 m, the terrace drops off and the reef slope commences. The dropoff zone exhibits maximum diversity of benthos and maximum coral cover (Bak, 1977). The reef slope drops down steeply at a 20-50° angle to depths of 25-55 m where it flattens out into a shelf. A second dropoff occurs beyond this (van Duyl, 1985). Van’t Hof (1982) recognized six distinct coral zones from the shoreline to 50 m. These are: a shore zone (0-1 m), characterized by Diploria clivosa; an elkhorn zone (1-4 m), dominated by Acropora palmata, Millepora sp., and crustose coralline algae; a staghorn zone (4-7 m), characterized by Acropora cervicornis interspersed with Madracis mirabilis, Colpophyllia natans, and Montastraea annularis and bounded by gorgonians; a dropoff zone (7-12 m), characterized by gorgonians, Montastrea annularis, Madracis mirabilis, and Eusmilia fastigiata; an upper reef slope (12-25 m), characterized by massive Montastrea annularis and Agaricia sp.; and finally a lower reef slope (25 m+), dominated by Agaricia sp. and some flattened forms of Montastraea annularis, Montastraea cavernosa, and Stephanocoenia michelinii but with few other abundant corals. A conspicuous feature of the reef slope, especially along the northwestern shore, are coral tongues (spurs) separated by sediment channels (grooves) which may form as a result of the inherent instability of corals at the top of the reef slope causing the reef to collapse locally. True spur-and-groove coral formations occur in shallow water at only two sites on Bonaire on the northwestern shore (Boca Bartol and Playa Benge). Along the windward shore, coral development is virtually absent in water shallower than 12 m, where there is an abundance of crustose coralline algae and dense stands of Sargassum platycarpum that may extend to 40 m water depth. Bonaire’s reefs were mapped in 1983, and detailed maps were produced of the shallow coral communities to a depth of 10-12 m along the leeward shore and Klein Bonaire (van Duyl, 1985). In addition to storm damage, significant natural impacts on Bonaire’s reefs during the 1970s and 1980s include an outbreak of white band disease (1980-1982), which caused the death of 90% of the standing stock of Acropora cervicornis, and the mass mortality of Diadema antillarum (1985) thought to be caused by a water-borne pathogen. Both events affected the entire Caribbean Basin to a greater or lesser extent. Bonaire supports some of the best remaining coral reefs in the Caribbean, with exceptionally high coral cover and exceptionally large populations of predatory fish (Roberts and Hawkins, 1994). The importance of maintaining healthy reefs both for their own intrinsic value and to ensure a sustainable economy for the island of Bonaire cannot be overstressed. The CARICOMP coral reef monitoring site, known locally as Barcadera, is situated at 12°11'45"N, 68°18'00"W. This site is on the leeward shore of Bonaire, north of the town of Kralendijk, and consists of typical Montastraea annularis dominated fringing reefs at the 10-12m depth range. The stony coral cover ranges from 20 to 40%. The site is located approximately 400 m from the nearest dive mooring and gives only limited shore access via an open rung ladder from a low limestone cliff. Land use at this area has changed dramatically over the past five years, particularly with the building of up-scale residential housing in a previously undisturbed natural area. Increased sedimentation through land clearance and landscaping is affecting the reefs, as is increased nutrient loading from sewage. As the coastal zone has now been developed, perhaps land use has stabilized for the foreseeable future. Because the prescribed 10-12 m depth range corresponds to the dropoff zone, transects were laid out oblique to the coast so as to fall within the prescribed depth range in two adjacent groups of five transects. Within the groups, transects are approximately 2 m apart. Data collected at this site show a reef benthos dominated by massive stony corals (29.4 % mean cover) and algae (33.0% mean cover), with few soft corals (2.4% mean cover) or sponges present. Bellairs Fringing Reef Actively growing, shallow, fringing coral reefs are found along most of the west (leeward) coast of Barbados, extending about 300 m from the shoreline (Lewis, 1960; Oxenford et al., 1993). Monthly mean seawater temperatures off the west coast range from 29.6°C in autumn to 26.0°C in February (Sander and Steven, 1973; Johnson, 1994). Monthly mean salinity varies from 32 to 36‰ (Johnson, 1994); the lower salinity results from water masses drifting northwards from the Amazon River (Ryther et al., 1967). Tides are mixed semidiurnal, with two low and two high tides every 24.8 hours and with significant diurnal inequality. The maximum tidal range is 1.1 m. The Bellairs fringing reef is located directly in front of the Folkestone Park beach and the Bellairs Research Institute within the Barbados Marine Reserve. Net current speed recorded at Porters, just south of Bellairs in 1983, was 0.12 m s-1, with little significant seasonal variation (Cambers, 1984). However, the net current direction observed in the vicinity of the Bellairs fringing reef appears to be highly variable. Murray et al. (1977) observed a flow towards the north in this area, Vezina (1974) recorded a flow towards the southwest, and Ott (1975) postulated the existence of eddies in the area of the bank reef. Cambers (1984) reported that a dominant current flowing towards the northwest was recorded 22 out of 46 times, a southwest current 20 out of 46 times, and an onshore wind-driven current during the remaining four observation periods. These data suggest that the Bellairs fringing reef may be located in an area where major current streams from the south and north of the island meet (Cambers, 1984). A triangular sand channel divides the reef into two unequal sections, with the southern lobe extending 200 m seaward and the northern lobe extending 100 m seaward. During most of the year, the sand separating the two lobes terminates in a narrow beach. However, the beach is seasonally unstable and is often completely eroded during periodic high swell events, which occur between November and March. The CARICOMP monitoring plots are located in the spur-and-groove zones of the north and south Bellairs fringing reefs, in the areas of highest live coral cover. The swash zone or backreef area of the fringing reef is narrow (20-30 m) and lies in depths ranging from 0 to 1 m. This area is composed largely of dead coral rubble covered by filamentous algae and mobile sand. The crest zone extends 40 m from the seaward edge of the swash zone, usually in water depths of 1 m, is occasionally exposed during very low tides, and comprises mainly coralline algae coating dead coral. The crest zone is responsible for reducing the wave energy reaching the backreef area by about 75%, calculated from reduction in wave height (Roberts et al., 1975). The coalesced spurs zone supports several mixed species of hard coral in depths ranging from 1 to 2 m. The outermost zone of the reef is the spur-and-groove zone. The spurs range in width from 3 to 10 m, and the tops of the spurs lie in water depths of 1 to 3 m. The largest proportion of living coral is found on the reef spurs. The coral species composition has changed periodically over the years. From examination and radiocarbon dating of the reef framework, Lewis (1984) suggested that Acropora palmata was a major component of the coral community up to the early 1900s, but that it has declined considerably in abundance since then. A dramatic change in the coral community resulted from the passage of Hurricane Allen in 1980. Porites porites was the dominant coral species on the reef prior to Hurricane Allen, according to Stearn et al.. (1977). A re-survey of the reef after the hurricane (1981-1982) indicated that Porites porites coverage had been reduced by 96% and that Agaricia agaricites had become the dominant coral species. The north and south lobes of the reef lie within the northern limit of the Barbados Marine Reserve, which was established in 1981. Thus, fishing is prohibited in this area and boat use is limited to authorized vessels. However, the area is very popular for recreational swimming, snorkeling, and diving. The area is also periodically exposed to heavy sediment loads originating from surface water runoff out of the nearby Holetown Hole, a narrow brackish water lagoon to the south, and it is also impacted by a general deterioration in nearshore water quality over the last 20 years (Johnson, 1994). Contaminated surface water runoff, ground water seepage, and waste water effluent pipes along the coastline have resulted in elevated nutrient levels (particularly NO3-NO2-N and PO4-P), and signs of eutrophication are obvious in the reef community (Tomascik and Sander, 1985). However the size, shape, and zonation patterns of the reef have not noticeably changed. Bermuda Reef Extensive reef zones are developed at the margin and on the shallow flanks of the Bermuda Pedestal. The Rim Reef is a shallow (3-10 m) zone, about 0.5-1 km wide, that separates the ocean from the North Lagoon. This zone is reduced on the narrow southeastern edge of the pedestal adjacent to the islands, where a nearly continuous linear sequence of emergent algal-vermetid reefs ("boilers") separate the nearshore reef zone from the ocean (Meischner and Meischner, 1977). Seaward of the northern Rim Reef and southern boiler reefs is the extensive Main Terrace, sloping between 15-30 m, that surrounds the entire pedestal and may be up to 3 km in width. Below the Main Terrace reefs is the deep fore-reef that slopes sharply off and terminates at about 60 m (Fricke and Meischner, 1985). Within the North Lagoon is an extensive array of patch reefs varying in size and configuration (Garret et al., 1971; Logan, 1988), interspersed with deep (15-18 m) muddy basins. The Rim and Terrace Reefs have similar coral assemblages, made up of a few species, but coverage ranges from 25% in the former zone to 50% in the latter zone (Dodge et al., 1982; Logan, 1988). Diploria strigosa, D. labyrinthiformis, Montastraea franksi sensu (Weil and Knowlton, 1994), M. cavernosa, and Porites astreoides are the dominant corals in these zones, along with the hydrozoan Millepora alcicornis. Less common species include Stephanocoenia michelini, Favia fragum, Agaricia fragilis, Madracis decactis, Siderastrea spp., Scolymia cubensis, and Isophyllia sinuosa. The deep fore-reef community is composed of Montastraea spp., A. fragilis, S. michelini, and Madracis spp. (Fricke and Meischner, 1985). The lagoonal patch reefs have a similar Diploria-Montastraea-Porites community structure with lesser coverage (<20%) (Dodge et al., 1982; Garret et al., 1971). However, the patch reefs closer to the island and within Castle Harbour support a different community of primarily branched species (Madracis decactis, M. mirabilis, Oculina diffusa) that grow on the vertical sides of the reefs (Dryer and Logan, 1978; Logan, 1988). This reef community may have developed as the result of higher sedimentation rates close to shore and the degree of protection from wave energy. Coral diversity is greatest on these reefs, along with other sessile invertebrates and benthic algae. Coral growth rates appear to be seasonal, with faster growth in the summer months but reduced for some species compared to Caribbean congeners (Logan and Tomascik, 1991). Higher growth rates for several coral species are found within the lagoonal reefs compared to the outer reef zones (Logan et al., 1994). Overall, Bermuda’s reefs are in good health, despite repeated coral bleaching episodes (Cook et al., 1993). The reefs have suffered direct human impact (ship groundings, dredging) but these have generally been limited in extent (Cook et al., 1993). The potential effects of the over-harvesting of reef fishes have been mitigated by a new management plan that eliminates the use of non-selective traps and creates no-fishing zones (Butler et al., 1993). Recent monitoring has noted the recovery of some fish stocks (Luckhurst, 1994). The CARICOMP reef sites are located on the northern rim reef about 12 km from the island. The Hog Breaker site (32°27'32"N; 64°49'54"W) and the Twin Reefs site (32°27'51"N; 64°48' 56"W) have been used for extensive investigation of coral recruitment, mortality, algal abundance, and fish grazing activity since 1986 (Smith 1988, 1990, 1992; Hog Breaker = Smith’s WC and Twin Reefs = Smith’s EC). Monitoring of coral bleaching on permanent transects at both sites has been carried out since 1990 (Cook et al., 1993). Neither site shows any evidence of human interference apart from low-impact scientific endeavors (photography, algal collection, installation of marking stakes). The reef sites are near the center of the Rim Reef zone, about 100-150 m shoreward from the transition of the Rim Reef to the Main Terrace; thus, these sites are exposed to oceanic swell and storm waves. Both sites are characterized as a bank of reef, average depth 7-9 m, interspersed with sediment-filled depressions at about 10 m depth. The reef surface is a fairly rugose relief of 1-2 m, due in part to the large sizes (0.5-1.5 m diameter) of the main framework-builder, Diploria spp. (Smith 1988). An unusual feature is the presence of occasional biogenic carbonate pillars up to 4 m in height and 1-2 m in width, with sparse coral cover (Logan, 1988). The coral communities at both sites are the Diploria-Montastraea-Porites assemblage typical of the Rim Reef. Gorgonian corals are common, primarily Pseudoplexaura spp., Plexaura spp., Eunicea spp., Pseudopterogorgia spp., and Gorgonia ventalina. Other common sessile invertebrates are coralliomorpharians, zoanthids, and anemones. Large erect sponges are rare. Reef turf algae are primarily Polysiphonia spp., Ceramium spp., Herposiphonia secunda, and Sphacelaria sp. The most common macroalgae are Laurencia obtusa and Dictyota bartayresii, although Ceramium nitens becomes seasonally dominant in the summer months (Smith, 1990). Boca Chica Reef Buccoo Reef North of the Bon Accord Lagoon is the extensive, shallow reef lagoon of Buccoo Reef. Small coral formations, characterized by one or a few species, occur throughout the reef lagoon. Four types of these patch reefs have been identified (Hudson, 1984). Patch reefs of finger coral (Porites porites) occur in the Bon Accord Lagoon and south of it. The patch reefs in the western area of the reef lagoon are composed of thickets of staghorn coral (Acropora cervicornis), while those in the eastern area are composed of both staghorn and fire coral (Millepora spp.). The patch reefs in the northern area of the reef lagoon consist primarily of large formations of star coral (Montastraea annularis) and brain coral (Diploria strigosa). Due to the presence of sea fans (Gorgonia ventalina) and other octocorals, as well as numerous colorful reef fishes, this northern patch reef locality is popularly known as "Coral Gardens." Five emergent reef flats arc seaward of the reef lagoon, from Pigeon Point in the west to Sheerbird’s Point on the east, known as Pigeon Point Reef, Western Reef, Northern Reef, Outer Reef, and Eastern Reef. The reef flats are separated by sandy-bottom channels, the widest and deepest of which is the Deep Channel between the Western and Northern Reefs. The reef flats are generally characterized by a narrow seaward reef crest and a more extensive backreef toward the reef lagoon. The reef crests coincide with a conspicuous breaker zone. Due to the turbulent nature of this zone, the faunal composition of the reef crests is limited to wave-resistant corals such as M. annularis, and elkhorn coral, A. palmata. Generally, the backreef areas are characterized by coral rubble (Kenny, 1976). West of the reef flats, the forereef slopes gently to a depth of 20 m. To the east, the forereef slopes to a depth of 15 m, while to the north the forereef slopes gently to depths over 30 m (Laydoo, 1985). The benthic fauna of the forereef is dominated by large colonies of stony corals. In the shallow forereef zone (2-6 m depth) A. palmata is common. In deeper areas of the forereef, large colonies of Diploria spp., Montastraea spp., and starlet coral (Siderastrea spp.) are common. The substrate of the shallow forereef is mainly composed of rubble and dead standing remains of A. palmata (Laydoo, 1985). Calabash Reef Stoddart (1962) established a reef transect from Little Calabash Island into deeper water, which showed reef zonation east of Calabash Caye after Hurricane Hattie (Table 1). A more recent study of coral distribution was conducted by the Planetary Coral Reef Foundation in 1992, using a chain transect and video. The study site was on Calabash Reef 2 km south of the channel separating Calabash Caye from Blackbird Caye, an area representative of the most well-developed region on the windward reef. Their 900 m transects extended from behind the reef crest seaward to a depth of 45 m. The results of these two surveys found Calabash Reefs having a clear zonation pattern of a windward West Indian coral reef with a backreef, reef crest, spur-and-groove zone, mixed zone, forereef terrace, escarpment, forereef, and deep forereef. The coral coverage varied, with the highest coverage in the spur-and-groove zone. Approximately 29 sceractinian species were found, not including separation of Montastraea annularis into subgroups; this was 69% of the hermatypic species in the area. Algal cover exhibited a pattern of increasing abundance with increasing depth. The cover was 30% in the spur-and-groove zone and increased with depth. Sea urchin abundance decreased with depth, with a mean of 83 urchins per search period in the spur-and-groove zone to a low of 3 urchins on the forereef slope. Urchins larger than 10 cm on the reef crest were Diadema antillarum; the dominant species in the spur-and-groove zone was Echinometra viridis (Dustan et al., 1992). Table 1. Reef transect seaward from Little Calabash Island just after Hurricane Hattie. Zones and Description from Stoddart (1962) Sand and rubble platform adjacent to the caye. There is about 12 inches of water on this platform and it is about 200 feet wide. It is carpeted with Thalassia and other green algae, including Halimedia. Near the outer edge of the platform Porites rubble becomes prominent. Reef flat - A sandy area under 18 inches of water 20-30 feet wide. Small corals (Favia fragusm and Porites divaricata) and sea-urchins (Diadema) are scattered in the turtle grass. Inner reef zone - A sandy area under 2 feet of water, with scattered colonies of Montastraea annularis, Porites asteroides, and Dendrogyra cylindrus about a foot high, with small colonies of Siderastrea siderea. Also, sea fans and sea whips are found here. Cervicornis zone - The ground is covered by Acropora cervicornis, much of which is dead. The Montastraea and Porites colonies are larger. Annularis zone - Large blocks of Montastraea annularis, Porites asteroides, Dendrogyra cylindrus, and Siderastrea siderea. Also present are encrusting and foliaceous Agaricia with Acropora cervicornis and Acropora palmata. This zone is approximately 8 feet deep and 15 yards wide. Reef crest (Agaricia) - This is made up of massive blocks of mostly dead corals covered with Agaricia agaricites. Channels between the blocks are 10 feet deep. This area is only a few yards wide. Outer slope A - platform from 10 to 15 feet deep and deepening toward the sea. Colonies of Montastraea, Porites, and Siderastra are 2 feet in average. Low colonies of Acropora palmata are also found in this area. The results of both these previous studies show that Calabash Reef is a thriving windward West Indian coral reef community with signs of hurricane damage on the populations of some coral species. In the early 1990s, coral bleaching was found throughout the Caribbean but Belize was seemingly spared. However, from August to October of 1995, NOAA satellites detected elevated sea temperatures spanning much of the Gulf of Mexico and the western Caribbean basin from Belize to Jamaica, Honduras, and Venezuela. It was at this time that coral bleaching was reported for the first time in Belize (Stout, 1995). Carrie Bow Cay Reef Site I of the CARICOMP reef transects was established approximately 200 m north of Carrie Bow Cay. Site II is approximately 100 m south of Site I at the same depth (13 m). Both sites are located on the upper edge of the inner reef slope that marks the transition from the inner to the ourt forereef habitats. The inner forereef zone at Carrie Bow Cay begins seaward of the reef crest with the high-relief spur and groove zone. This zone is characterized by large, well-developed buttresses separated by sand channels (Rützler and Macintyre, 1982b). Percent coral cover ranges from near zero to >60%, and topographic complexity ranges from <0.20 to >0.80 (Aronson and Precht, 1995). In a 1980 survey, algal abundance was low (about 4.5%) and consisted primarily of Porolithon and Halimeda opuntia (Littler et al., 1987). This zone is composed of two overlapping subzones: a shallower set of spurs (0-3 m depth) dominated by Acropora palmata and Millepora spp., and a slightly deeper set of spurs (3-6 m depth) dominated by Agaricia tenuifolia (Rützler and Macintyre, 1982b; Aronson and Precht, 1995). Dominance of the high-relief spur and groove subzone by A. tenuifolia contrasts with many Caribbean reefs in which reef buttresses are constructed primarily by massive corals such as Montastraea annularis. Chornesky (1991) showed that this results from the ability of A. tenuifolia to modify its skeleton so that contiguous, genetically distinct colonies become anchored against each other to form a relatively stable honeycomb of coral skeleton that monopolizes space on the spurs. Other abundant species in this zone include Acropora cervicornis, Porites porites, and P. astreoides. Prior to the major die-off of Diadema antillarum throughout the Caribbean (Lessios et al., 1984), this zone also contained the highest density (4.3 individuals/m-2) of D. antillarum (Lewis and Wainwright, 1985). The low-relief spur and groove zone (10 m depth) of the inner forereef is a broad shallow slope best described as a hardground that is regularly interrupted by shallow sand channels. The low (about 1 m relief) coral ridges are formed primarily of Montastraea annularis, M. cavernosa and Diploria strigosa (Rützler and Macintyre, 1982b). Much of this area is densely covered with gorgonians dominated by Pseudopterogorgia species (Lasker and Coffroth, 1983). Briareum asbestinum and Muriceopsis flavida are the two most abundant octocorals on the CARICOMP transects. Demospongea and scattered coral heads, primarily M. annularis, also dominate this area (Lewis and Wainwright, 1985). Littler et al. (1987) found that macroalgal abundance in 1980 was extremely low (about 2.5%) in this zone and composed of epilithic forms on the reef rock and scattered rubble. Spatial heterogeneity (3D structure) is high (mean rugosity on CARICOMP Coral Reef Site I 1.71) and herbivorous fish are abundant, reaching their maximum density in this zone (Lewis and Wainwright, 1985). The transition from the inner forereef to the outer forereef zones occurs at the seaward edge of the low-relief spur and groove where the gradual slope of the inner forereef abruptly changes to a steeply sloping (25°) zone of hard corals and sponges. Columnar colonies of Montastraea annularis at the top of the slope give way to large platy colonies toward the base that are accompanied by Porites astreoides, Siderastrea siderea, and Agaricia spp. (Rützler and Macintyre, 1982b). Until the late 1970s, this zone was dominated by Acropora cervicornis (Rützler and Macintyre, 1982b; Burke, 1993). By 1984, most of the A. cervicornis had died off, apparently from white-band disease (Peters, 1993; Aronson and Precht, 1997; Macintyre and Aronson, 1997). At some Belizean reef sites, A. cervicornis has been replaced in the interim by Agaricia spp., possibly due to high levels of herbivory by the echinoid Echinometra viridis (Aronson and Precht, 1997). In the shallow backreef zone at Carrie Bow Cay, the disappearance of A. cervicornis has been accompanied by a proliferation of Porites porites, an opportunistic species that is starting to overgrow some of the slower growing massive corals (Macintyre and Aronson, 1997). However, in the deeper forereef areas at Carrie Bow Cay, most of the A. cervicornis has been replaced primarily by macroalgae (principally Lobophora variegata, Dictyota spp., and Halimeda spp.). The faunal transition from dominance of hard corals to macroalgae accompanying the demise of A. cervicornis is reflected in the relatively low percent coral cover and high algal (macrophyte) cover presently observed at the CARICOMP sites. This is particularly evident at Site I, where macroalgal cover has increased from approximately 3.4% in 1980 (Littler et al., 1987) to about 45% at present, while coral cover has dropped from an estimated 30-35% in the late 1970s (Rützler and Macintyre, 1982b) to around 12% today. A similar decline in coral cover from the 1970s to the 1990s from natural disturbances has been noted in the Gulf of San Blas, Panama (Ogden and Ogden, 1993). Cayo Coco Reef The coral reef transects are located at a depth of 10-12 m across a very poorly defined spur-and-groove bottom or a rather rocky-sandy bottom with coral mounds (A, 22°33'49"N, 78°26'19"W; B, 22°33' 48"N, 78°26'42"W). This transect area is located in the forereef zone adjacent to an escarpment that drops from 12 to 15 m; the area is rich in corals, sponges, and gorgonians. The adjoining lower terrace on the forereef slope is a rocky plain that is covered by a sand layer of varying thickness and extensive patches of Syringodium filiforme (surveyed to a depth of 20 m). At both reef sites, bottoms exhibit irregular patterns of mounds, sand grooves, and patches. The relief is accentuated towards the 12 m contour, where the escarpment begins. The reef data are averages from both transects from March 1994 to April 1995. At each transect, the mean coral cover, including sand patches, varies from 5.5 to 7%. The dominant scleractinians are Montastraea annularis, with 10-55% of cover among scleractinians, M. cavernosa (3-22%), Porites porites (3-26%), and Siderastrea siderea (3-17%). Gorgonians and sponges are fairly abundant and moderately developed; sponges cover 2-3% of the bottom. The most common sponges are Aplysina cauliformis, Ircinia felix, Iotrochota birotulata, and Niphates digitalis. Most common among the gorgonians are Pseudopterogorgia americana, Briareum asbestinum, and Plexaura homomalla f. kuekenthali. The rocky substrate is covered by a mat of fleshy algae, including Dictyota, Lobophora, and Microdictyon, that is covered by sand. Fleshy and turf algae cover 52-60% of the bottom. From a depth of 10 m to 2 m, the bottom grades from a poorly defined spur-and-groove system to plain rock pavement, dominated by gorgonians. A discontinuous reef crest consists of a line of rocky outcrops covered by abundant colonies of fire corals (Millepora complanata), sea fans (Gorgonia flabellum), and small, sparse colonies of elkhorn corals (Acropora palmata). At both ends of the reef crest, extensive low-relief sandy rock pavements with gorgonians penetrate deeply into the lagoonal area, showing the abrasive influence of open ocean waves and perhaps tidal currents. The bottom of the rear zone is homogeneously covered by abundant coral rubble, profusely colonized by brown algae (Dictyota and Stypopodium). In the reef lagoon, the rubble bottom is colonized by sparse short-leaved Thalassia. The bottom slopes from the shore to the sandy sparse Thalassia beds of the reef lagoon. Extensive sandy areas, without vegetation, occur among the grass beds. The nearshore bottom is void of macrophytes, although some, mainly Thalassia, occur in elongated patches. Dominant fishes, at depths between 3 and 15 m, belong to the families Haemulidae (Haemulon plumieri, H. flavolineatum and H. sciurus), Labridae (Thalassoma bifasciatum and Halichoeres bivittatus), Pomacentridae (Stegastes spp.), and Scaridae (Sparisoma spp. and Scarus spp.). At depths of 15 to 25 m, specifically on the deep slopes, the predominant families are Labridae (T. bifasciatum and Clepticus parrai), Pomacentridae (Chromis cyanea and S. partitus), Inermiidae (Inermia vittata), and Scaridae (Sparisoma spp. and Scarus spp.). The most important physical stressors on this reef are wave action and natural sedimentation. Freshwater sources are limited. Human impacts on these reefs are negligible so far, limited to lobster fisheries and some tourism. The virtual absence of the herbivorous black urchin, Diadema antillarum, may account for the great proliferation of algae on the rocky substrates of this reef. Cayo Sombrero Reef Cayo Sombrero is a sandy key surrounded by coral reefs. The CARICOMP station, established in June 1996, is located on the lee side of the key; however, the reef is influenced by strong lateral currents due to the bottleneck configuration of the key system. The main reef is separated from shore by a shallow sandy channel 80 m wide. There is not a genuine reef front. The shallow reef (3 m depth) is covered mainly by soft corals such as Pseudoplexaura sp., Plexaura homomalla, P. flexuosa, and Pseudopterogorgia americana. The predominant hard coral at this depth is Madracis mirabilis. The slope begins at a depth of 4 m; it reaches 15 m on the southern side and 6 m on the northern side. The CARICOMP station is located in the southern zone characterized by the deeper slope. Between 3 and 5 m deep, the community is represented by Millepora alcicornis and Madracis mirabilis. Down to 12 m, large colonies of M. annularis dominate the reef, with some conspicuous colonies of C. natans. There are also some colonies of M. cavernosa, D. strigosa, P. porites, and A. agaricites. The reef ends at a depth of 15 m with a gently sloped sandy bottom. In general, this station is structurally more complex than Playa Caimán, although M. annularis does not have large vertical formations. Chengue Bay Reef Werding and Sánchez (1989) reviewed the information on corals in the Santa Marta area, indicating that reef development is impaired by continental run-off, lack of adequate substrate for reef settlement, and low water temperatures due to the local upwelling, although coral communities are diversely structured and rich in species. These investigators described eight types of coral communities in the bays of Parque Natural Tayrona, and discussed specific species composition and form of colonies. The most outstanding factor in determinating variation in community structure is degree of exposure to the predominant wave impact along the shore of the bay. Coral communities from Chengue have been described by Werding and Erhardt (1976), Solano (1987), and Garzón-Ferreira and Cano (1991). Thirty-one species of hermatypic corals plus three hydrocorals of the genus Millepora are known in Bahía de Chengue. Although corals are present along the coastal rocky belt of the bay, only in areas protected from direct northeasterly ocean wave action have they grown sufficiently to modify the bottom morphology as true coral reefs. Two main types of coral reefs are identified in Chengue: narrow, short coastal fringes growing over the belt of metamorphic rocks in the northern deep half of the bay, and extensive fringes growing away from shore on sedimentary flats of the bay. Although some Acropora palmata can be found in shallow water, the coastal fringes are dominated by massive and encrusting corals (mainly Diploria, Montastraea, and Colpophyllia), which form a reef slope extending to a depth of 15-25 m, <70 m from shore. In contrast, the inner fringes of the bay have extensive shallow reef flats, dominated by foliaceous and branching corals, which become reef slopes covered with massive corals at depths of 6-8 m. The southeastern inner fringe at depths between 3 and 6 m is dominated by large and dense Agaricia tenuifolia stands, with wide patches of Madracis mirabilis on the upper reef slope (6-10 m). The western inner fringe is more exposed to wave action and has a shallow zone dominated by Acropora palmata (1-4 m), with abundant Millepora squarrosa and Palythoa caribbea on the upper reef crest. As in many other areas of the Caribbean, shallow water coral formations in Chengue Bay have suffered considerable mortality among branching (A. palmata, A. cervicornis, Porites porites) and foliose corals (A. tenuifolia) over the last decade (Garzón-Ferreira and Cano, 1991). CARICOMP coral reef stations in Chengue are located at depths between 9 and 12 m at two coastal sites separated by 400 m. Due to the short horizontal extent of the coral communities, the CARICOMP random method for location of transects could not be applied in Chengue. Transects were placed arbitrarily following depth contours, trying to maintain the same community type. The coral community at the northern site (C2) is exposed to swells, which can reach considerable heights on days of strong trade winds; as a result, branching or foliaceous corals are almost absent. The dominant forms are small to medium-sized coral heads, and live coral cover is high (mean 42% at five CARICOMP transects in 1993). Site C1 is rarely disturbed by waves and Acropora palmata is abundant in shallow water. The coral community at depths of 9-12 m is dominated by medium-sized coral heads, but it also includes some delicate species e.g., Leptoseris cucullata and Agaricia tenuifolia; live coral cover is lower (mean 26% at five CARICOMP transects in 1993). At present, algae are the most important component covering the reef surface at both sites. Discovery Bay West Fore Reef The actual CARICOMP coral reef site is situated in the mixed/buttress zone of the west forereef in 6-8 m of water. In 1977, this area was described by Woodley and Robinson as a mixed zone of high coral abundance and diversity; there were a few incipient buttresses, mostly consisting of numerous massive heads of M. annularis in a field of staghorn coral, Porites spp., and castle-like colonies of Dendrogyra cylindrus, with many other coral species and diverse gorgonians. In 1984, Liddell et al. reported that M. annularis had maintained its dominance, with colonies exhibiting great variations in size. Other branching and boulder corals were well represented, including species of Acropora, Porites, and Diploria. Sponge and algal diversity was usually low, whereas gorgonians of Briarium and Plexaurella spp. were reported as being common. At present - after two hurricanes, four bouts of bleaching, and a shortage of herbivores - the huge stands of the two Acropora species leveled in 1980 have not recovered. They have also suffered from "white-band" diseases. Meanwhile, the massive heads of Montastraea are being overgrown by the flat clinging leaves of Lobophora as well as other turf algae. Opportunistic corals have again recruited in small numbers on the terrace, but they are having to compete with numerous algae. Coincidently, the CARICOMP site is only a few meters from a permanent photoquadrat site at a depth of 6-7 m; coral cover here was measured in 1978 and found to be 54% (Porter et al., 1981). Data from the first five CARICOMP coral reef transects in 1993 returned an average hard coral cover of 17.7%. A further decrease in coral cover over the same five transects was demonstrated in 1994; hard coral cover was found to be 9.5%, with Montastraea spp. being the primary coral species. This level of coral cover was maintained during the 1995 and 1996 reef surveys, which utilized five and ten transects, respectively. The backreef area on each side of the bay supports a lagoon environment, with generally coarse calcareous sand, scattered coral heads, small patch-reefs, large beds of turtle-grass, and soft mud at its deeper points. Wave action from storms and norwesters scours the shallow area of the bay. At sheltered depths (>10 m), fine sediment accumulates and light levels are relatively low. Conditions on the sides of the deep basin (at 20 m depth) are similar to those on the forereef at 40 m depth. Species and growth forms generally characteristic of greater depths on the forereef are found here in the shallow waters of Red Buoy or Columbus Park reefs. Various forms of suspension feeders dominate the scene; while the diversity of the corals appears to be high in this region, they are not numerous. The shallow lagoon exhibits a transition from coarse sand along its margins to fine silt in its deeper regions, which are hummocked by intermittent burrow-mounds of the ghost shrimp - Callianassa spp. The usual assortment of mobile invertebrates is found, such as holothurians and grazing, rock-boring, and burrowing echinoids (Aller and Dodge, 1974), in addition to numerous cnidaria such as Condylactis gigantea and Cassiopea xamachana. Small patch and fringing reefs occur, especially on the southern and western margins. Quantities of coral rubble, mostly old slabs of A. palmata, beneath which is a rich invertebrate fauna, are found within 100 m of the reef flat. Approaching the rear zone, extensive carpets of coelenterates such as Stoichactis and Palythoa spp. are found in the sand as well as covering hard substrate. These mats are interspersed with isolated heads of boulder corals - M. annularis and S. siderea (many of them dead and eroded) as well as the more delicate P. porites. The lagoon contains abundant algae, including the calcareous greens Halimeda and Penicillus spp., which are major components of backreef sediment (Liddell et al., 1984). Extensive carpets of Chaetomorpha linum grow in the well-lit shallow waters during warm summer months, covering the bottom sands. During windy weather that creates rougher conditions, these mats slough off the bottom and float around the bay. Eduardo Reef The coral reef is characterized by an outer crest extending for 5 km around Punta Cahuita; the forereef base is at a depth of 15 m. The reef crest is dominated by Millepora complanata Lamarck and coralline algae. A smaller inner crest extends for 500 m around Puerto Vargas; the base of the forereef is at 5-6 m and is built mainly of Agaricia agaricites (Linnaeus) and Porites spp. on the eastern end, and of massive corals in other sections. The reef crest had Acropora palmata (Lamarck), but the species died off in 1983 (Cortés et al., 1984) with little recovery since then. The backreef has Diploria clivosa (Ellis & Solander) and Millepora complanata; the lagoon is mainly rubble, with a few seagrasses and algae. The CARICOMP site is located on the inner crest at the base of the reef at a depth of 5 m. El Peñón Reef Four of the benthic sites are characterized as belonging to the low-relief spur-and-groove community: Parque Nacional and El Peñón (where the CARICOMP site is located), both of which are on the west side of the park, are the most representative of this category; Arrecife de Rubén is located on the western coast of Saona Island; El Toro is also located on the western coast of Saona but farther south. These sites are relatively protected from direct wave action by land barriers. They lie in water depths of 15-25 m and have well-defined but low relief (<1m) spur-and-groove features. They do not appear to be actively accreting. The substrate in low-relief spur-and-groove communities is mostly hard reef, but crevices, depressions, and space grooves are filled with sediment. The life form data show that these communities are characteristically dominated by algae, sponges, and octocorals, while hard coral cover is very low. Diversity of all lifeforms is high, and it is in this reef category that we find the sites with some of the greatest octocoral species richness (El Toro with 22 species), sponge species (El Peñón with 36 species), and hard coral species (El Peñón with 26 species). Most algae are calcareous (Halimeda) or turf algae, although Dictyota is also present. Octocoral and sponge individuals are characterized by large size. Corals, when found, are mostly Diploria labyrinthiformis, Siderastrea siderea, or Montastraea cavernosa. Three reef flat communities, consisting of low-relief consolidated carbonate platforms, are identified in the park: Pasa Grande, Arrecife del Tronco, and Arrecife de Fuertes Olas. All are in relatively shallow water (0.5-3.0 m) on the eastern portion of the channel between the mainland and Saona Island. They are thus subjected to heavy wave action and strong currents from the Mona Passage. Life form characteristics in reef flats vary substantially. Pasa Grande is dominated by algae cover (in more than three quarters of the quadrats, the coverage is 72%), although sparse hard coral colonies (Acropora palmata, Diploria clivosa, Porites astreoides, Porites porites) are also present. The greatest algal species richness, especially of phaeophytes, occurs at this station. The most important algae here are the genera Dictyota, Turbinaria, Stypopodium, and Halimeda. Arrecife del Tronco is also dominated by algae, although not as strongly as Pasa Grande. There is sparse to moderate sponge and hard coral (mostly Porites porites forma furcata) cover at this site. Arrecife de Fuertes Olas is also strongly dominated by algae, with some sparse hard corals and seagrasses present. Three patch reef communities were identified in the park. Arrecifes del Angel #1 and #2 are both relatively circular in shape and are surrounded by a sand halo and then a seagrass bed (Thalassia testudinum). It has been shown that these sand halos can be caused by nocturnal grazing activities of long-spined Diadema antillarum sea urchins, which move out of their hiding places on the reef at night to feed on the adjacent seagrass beds (Vega, 1990). The substrate at Arrecife del Angel #1 consists of nonconsolidated rubble or cemented dead Porites porites corals, with sediment increasing towards the periphery of the reef. The substrate at Arrecife del Angel #2 is a mixture of hard reef, sediment, and rubble. El Faro #1 is a heterogeneous series of patches separated by sediments and rubble from Acropora cervicornis. The substrate itself consists of a consolidated reef platform with some coral heads. The dominant biota in all three patch reefs is algae. At Arrecifes del Angel #1 and #2, algae covers >50% of the quadrats in 72% of the area. Dictyota are very common at El Faro #1. Although sponges, octocorals, and hard corals occur in all three patch reefs, El Faro #1 and Arrecife del Angel #2 are also characterized by having a diverse octocoral and hard coral fauna. For example, El Faro #1 is the only place where Agaricia tenuifolia is found and where colonies of Millepora squarrosa are also common. This latter coral species is found only at the El Faro #1 and #2 stations. Hard coral and octocoral species are also very common at Arrecife del Angel #2, where large colonies are abundant. Fernandez Bay Reef The coral reef site is located at 24°02'12"N, 74°31'57"W in Fernandez Bay, a gently curving shallow embayment along the west coast of San Salvador. The bay is 4-5 km wide and extends from Cockburn Town in the north to the Sugar Loaf Rocks in the south, a distance of 6-8 km. The dominant feature of the irregularly shaped shoreline is the presence of large blocks of lithified beach sand which extend from the upper reaches of the intertidal zone (splash zone) through the lower intertidal zone and into the sandy bottom of the bay. The intertidal extends approximately 25 m into Fernandez Bay, with a mean depth of 1.5 m at high tide. The beach rock shoreline of Fernandez Bay grades into a predominantly calcium carbonate sand and extends outward from the shore 400-1,500 m to the "dropoff" or "wall," with a gradual downward slope such that the water reaches a maximum depth of 15-25 m at the top of the wall. Numerous patch reefs of considerable size (>5,000 m2, 3-5 m high) appear randomly on the floor of the bay. Water visibility remains good most of the year, with an average Secchi depth of 60 m. The mean water temperature is 28°C. The wall is the predominant geological feature along the west coast of San Salvador Island; it has a near-vertical drop to 2,000-3,000 m. Running parallel to the shoreline and about 1,000 m from shore is a minor secondary dropoff that descends toward the top of the wall. The sampling site at Ostrander Reef is located within a band of coral reefs situated on top of the wall and extending a considerable distance both north and south of the site. The patch reefs scattered across the sandy bottom of the bay contain at least 100 species of fish and many more species of invertebrates. Hard corals include Acropora cervicornis, Porites astreoides, P. porites, Monastrea annularis, M. cavernosa, and Dichocoenia stokesii. The same soft coral species as described above predominate. In addition, significant numbers of colonies of Millepora sp. occur at a higher density on these reefs than on the surrounding substrate. The predominant algal species on the patch reefs include Padina and Turbinaria. Primary anthropogenic activities in the vicinity of the coral reef site include occasional recreational divers and fishermen that visit the wall. However, this site is not in close proximity to any regular dive sites or fishing spots. Consequently, little human impact on any aspect of this coral reef ecosystem is anticipated over the course of these studies. The coral reef site is located a considerable distance from the seagrass and mangrove sites, and little interaction between the three ecosystems can be expected. Grand Cayman Reef Grand Cayman has a narrow, insular, carbonate shelf, rarely exceeding 1.5 km in width and frequently less than 0.75 km. The submarine topography past the fringing reef of North Sound is characterized by two well developed spur-and-groove terraces (Rigby and Roberts, 1976), a shallow terrace reaching to a depth of 9 m, and a deeper one at 15 m that plunges into the abyss. Past the reef crest, the shallow rocky sill is dominated by alcyonarians, along with sparse colonies of Agaricia agricites, Siderastrea sidera, and Montastraea annularis. The latter two are the least abundant but form large prominent heads. Stony corals gradually increase in number seaward and away from this bedrock zone to a depth of 12 m, where large heads of Montastraea annularis (some up to 5 m in height) dominate. CARICOMP data indicate live benthic cover (excluding algae) and rugosity to be 24.15% and 1.7%, respectively. This is and may be attributed to the fact that the sampling area, as determined by the prescribed methodology at the 10 m contour, was more shallow than the best developed reef. Typically, there is a deep sand plain of varying width and depth separating this shallow terrace and the deeper terrace. The deep terrace is distinctive in that it has a dramatic relief, the highest diversity of stony corals, the greatest percentage cover of sponges, and the highest density of fish (Burgess et al., 1994). Great Corn Island Reef In 1993, a set of five permanent transects was established on the CARICOMP monitoring site. The site is located at latitude 12°11'59.4"N and longitude 83° 03'28.5"W, within the offshore reef system in an area in which the reef is part of the fringing reef that is found at a depth of 12-15 m. The reef terminates at 20 m, where extensive sand pools extend seaward (Roberts and Suhayda, 1983; Geister, 1983; Ryan, 1994). The site is in the path of the predominant trade winds and wave energy and sand is frequently resuspended in the water column. The only human influence near the monitoring site is sporadic fishing by lobster divers, occasional fish trapping, and occasional hook-and-line fishing. Based on chain transect surveys over the three year sampling period 1993-1995, mean substrate rugosity measured 1.91 (sd=0.132). Live cover at the site was dominated by algae (43.9%) and scleractinian corals (25.2%). Non-living substrate (e.g., gaps, holes, dead coral) made up 27% of the reef cover. Data on the abundance of hard, soft, and hydrocorals were collected using a combination of chain transect and meter-square methods in order to make a more representative species characterization of the site. A total of 28 coral species was found using the two different methods. Chain transects appeared to be more sensitive for finding smaller species (e.g., Scolymia, Mycetophyllia). Results indicated that a small group of coral taxa (Montastraea annularis, Agaricia spp., Porites spp., Millepora alcicornis, and Pseudopterogorgia spp.) represented over 90% of the corals sampled at the site. Algae were dominated by the "fleshy" species, Dictyota spp. and Padina spp. Abiotic substrate made up nearly one-quarter (23%) of the site. Sponges and soft corals represented less than 5% of the total cover. Video archives (8 mm video camera) were made by swimming 1 m above each of the 5 transects during each year from 1994 through 1996. Isla Colon Reef La Parguera Reef According to Almy (1969), coral reefs in La Parguera originated from erosion and deformation of Upper Cretaceous limestones (with interbedded mudstones and volcanic rocks) into a WNW-ESE trending syncline. The northern limb of the syncline is the Sierra Bermeja, and the southern limb is a platform of lower relief represented by the coral reefs on the shelf. The rise in sea level associated with the last Pleistocene glaciation (Wisconsin) flooded the lower limestone ridges on the shelf, providing appropriate sites for coral growth and subsequent reef development (Glynn, 1973; Goenaga and Cintrón, 1979). Cross-shelf seismic profiles (Morelock et al., 1977) support the theory of Kaye (1959), which states that the reefs developed on drowned calcarenite cuestas formed as eolianite structures parallel to the coastline during the Wisconsin glaciation. Substrate, depth, and water transparency conditions in La Parguera allowed for extensive development of coral reefs during the mid-Holocene (Vicente, 1993). Two distinct lines of emergent reefs align east-west, parallel to the coastline, and divide the insular shelf of La Parguera into inner, middle, and outer shelf zones (Morelock et al., 1977). There are many other smaller submerged patch reefs dispersed throughout the shelf, as well as a large submerged reef at the shelf edge. Altogether, it has been estimated that coral reefs occupy about 20% of the La Parguera insular shelf (Morelock et al., 1977). Margarita Reef, the westernmost in the second line of emergent reefs, is the largest of the "island reefs," with a maximum underwater extension of 4.2 km. The shelf-edge reef is located at 20 m and has a "buttressed" appearance, with channels cut into the slope down to 30 m (Morelock et al., 1977). Almy and Carrion-Torres (1963) reported 35 species of scleractinian corals, and at least 30 other species of shallow-water octocorals have been reported from La Parguera (Yoshioka and Yoshioka, 1989). A generalized pattern of coral zonation at the fore-reef of emergent coral reefs in La Parguera was described by Acevedo and Morelock (1988). Zonation is similar to other Caribbean coral reefs, except that the Lithothamnium ridge found elsewhere is replaced by Millepora in La Parguera. Turrumote Reef is located 3.5 km south off Punta Papayo, Lajas (17° 56.2'N; 67°1.2'W. Adjacent emergent reefs are Corral (~0.8 km to the north) and Media Luna (~2.0 km to the west). Turrumote Reef runs east-west with a longitudinal extension of 1.8 km; its emergent extension is 0.5 km along the E-W axis, and its total surface area is ~1.3 km2. This reef is situated on an isolated platform with its base at 20 m. The base substrate is covered with sandy silt sediments. Several other submerged reef platforms, rising to ~5 m from the surface, are located close to Turrumote to the southeast, including "Pinnacles." A small patch reef lies to the northeast, and a hard ground, low relief platform known as "Turrumote Ridge" is found to the southwest. The emergent section of Turrumote Reef is shaped like a horseshoe, forming a shallow reef lagoon at its center; this section is partially vegetated with red mangroves. Turrumote is farther offshore than any other reef in La Parguera. The fore-reef is characterized by a long reef crest, an abrupt slope that includes several terraces, and a deep reef zone of irregular topography featuring massive coral formations at the base. At its easternmost section, the fore-reef extends 0.8 km to the south as a low-relief platform dominated by soft coral. Elsewhere, the fore-reef has horizontal extensions of less than 100 m from the surf zone to the reef base. The back-reef of Turrumote lacks the typical sandy-silt substrate leading to turtlegrass beds (Thalassia testudinum) that is found on many other reefs in La Parguera. Instead, the back-reef presents substantial hermatypic, soft coral, and hydrocoral (Millepora) development on a mostly sandy substrate. The reef crest (depth 0-5 m) of Turrumote is a zone of energetic wave action dominated by encrusting biota: firecoral, Millepora spp., and branching coral, Acropora palmata. A dense algal turf composed of an assemblage of red and filamentous green algae covers most of the non-living hard substrate. The encrusting sponge Anthosigmella varians is found in multiple, small to intermediate patches (max 1.5 m diameter). Zoanthids, mostly Palythoa caribbea, and encrusting soft coral (Erythropodium sp.) are also common at the reef crest. Topographic relief ranges from 2 to 3 m and is influenced by the presence of large colonies of A. palmata . The reef slope (5-13 m) is an area of intermediate wave and surge action and good light penetration. Using CARICOMP methodology, five chain transects, 10 m long, were surveyed at the fore-reef slope of Turrumote Reef. Massive corals, mainly Montastraea annularis dominate linear cover with a mean of 41.2%. Branching coral (mostly Porites porites) represents an additional 6.6%, for a total of 47.8% of live coral cover at a depth of 10 m. Bell-shaped colonies of M. annularis are generally of large size, ending with extensive overhangs on the sides. Some of these colonies measure more than 4 m in diameter and are contiguous with other colonies, creating sections of live coral that exceed 10 m in length. In addition to M. annularis, other massive coral species that are present in excellent condition at the reef slope of Turrumote include Montastraea cavernosa, Dendrogyra cylindricus, Siderastrea spp., and Diploria spp. Algal turf follow live corals in linear cover, averaging 27.2% along the surveyed transects (range 13.9-38.3%). A highly diverse and abundant population of gorgonians represents another important component of the benthos at the reef slope. The deep fore-reef (13-20 m) is a zone of low wave and surge energy. Reef rugosity is irregular, influenced by the growth of massive scleractinian corals, particularly Montastraea annularis. As on the fore-reef slope, Montastraea colonies grow with extensive lateral projections, creating ledges and overhangs. Many massive coral colonies are overgrown by an algal turf, an encrusting soft coral (Erythropodium sp.), or a combination of both. The most common massive coral species at the deep fore-reef are M. annularis , M. cavernosa, Diploria spp., Siderastrea spp., and Dendrogyra cylindricus. A profuse development of soft coral colonies is also found at the deep fore-reef of Turrumote. Ladder Labyrinth Reef The CARICOMP coral reef monitoring site is located at 17° 37'34.0''N, 63° 15' 35.5''W on the leeward western coast of the island about 100 m north of a dive mooring in an area known as the Ladder Labyrinth. The transects are 100 m from the shore on a reef characterized by parallel coral ridges separated by sand channels. Van’t Hof et al. (1991) hypothesized that coral colonies in this area, which originally encrusted a volcanic boulder substrata, have fused to form a reef structure. This site has been characterized as a spur-and-groove reef. According to Deslarzes (1994), there is an average hard coral coverage of 24.3% ± 3.8 (SD). Impacts on this area are limited to sedimentation and recreational diving. Some volcanic hot springs occur near the shore but, according to seawater temperatures collected at this site, there are no unusually high temperatures. CARICOMP surveys to date have shown that the reef benthos is dominated by fleshy algae, turf algae, and sand. The dominant hard coral species are massive in structure, with Montastraea annularis covering approximately 42% of the total hard coral area. Physical data, including surface water temperature, light attenuation, and salinity, have been recorded weekly at the reef site since September 1992. Generally, salinity does not deviate much from 35‰. Light attenuation ranges from 12.5 to 30 m, averaging 22 m at this site. The average surface water temperature ranges from 26.5°C to 29.1°C. Playa Caimán Reef Playa Caimán is a fringing reef with a channel that breaks with the continuity of the reef and separates the area in two zones: northern and southern. The northern zone has been more affected by man-made disturbances (until 1974, there were three elevated houses located on a small inlet on the leeward side of the reef). The southern zone is more secluded and less disturbed; the reef platform is only 50 m wide and the reef slope reaches to a maximum depth of 12 m. The anterior zone of the platform borders the mangrove forest and a poorly developed Thalassia testudinum prairie. The mean depth of the platform is 0.3 m. The algal species reported for the platform are Halimeda spp., Dyctiota cervicornis, Caulerpa spp., Panicilum capitatus, Jama capillosa, among others (Weil, 1980). The coral species reported are Diploria spp., Millepora alcicornis, Siderastrea radians, and Porites astrecides. Extensive formations of the zoanthids Palithoa mamillosa and Zoanthus sociatus are found toward the reef front. Several species of sponges as well as soft corals of the Plexaura sp. are found in crevices in the reef. The reef front (0.20-3.0 m depth) is dominated by formations of Acropora palmata, which give rise to high morphological heterogeneity. Other colonies found here are Millepora alcicornis, Millepora complanata, and Montastraea annularis, which grow in columns. This zone continues with an extensive fringe dominated by Montastraea annularis (2.5-7 m in depth). There are also colonies of Colpophyllia natans, Diploria spp., Agaricia spp., and some colonies of Solenastrea bornuoni in this zone, the most homogeneous coral zone. The deepest zone of the reef (7.0-11 m depth) or slope is mainly dominated by large colonies of Colpophyllia natans and also by Montastraea cavernosa. There are also several well developed colonies of soft coral such as Pseudopterogorgia sp., Plexaura homomalla, P. dichotoma, and Eunicea sp. among the most abundant. This zone ends in a sandy bottom with a soft slope that continues down to 15 m depth, with dispersed patches of coral colonies of variable sizes (Bone, 1980). In January 1996, a mass mortality event affected many reefs in the park and left less than 1% of live massive coral cover at Playa Caimán. At this site, only P. porites, S. sidera, and Millepora alcicornis survived. An uncommon upwelling event combined with large river outputs enriched waters with nutrients, leading to an anomalous planktonic bloom. Huge amounts of macroaggregates were produced by dinoflagellates and diatoms, forming a mucous layer that covered the reefs. Very calm seas and low wind speeds kept the bloom within the park. This condition persisted for a week, inducing mortality among fishes, crustaceans, mollusks, equinoderms, annelids, sipunculids, sponges, and cnidarians by either mechanical asphyxiation (obstruction of respiratory mechanisms by a thick layer of mucus) or anoxia (reduction of dissolved oxygen by decomposition of organic matter). The station at Cayo Sombrero was slightly affected, as it was one of the few sites in the park still presenting an important live coral cover. Providencia Reef Isla de Providencia Puerto Morelos Reef Puerto Morelos is situated in the northern part of an extensive barrier-fringing reef tract that extends from Belize to the Yucatan Strait. In contrast to the southern reefs, however, reef development in the northern part of the tract tends to be limited to reef crests and backreef zones (Jordán-Dahlgren et al., 1981). The Puerto Morelos reef consists of an extensive calcareous platform that is bevelled on the seaward side, probably by eustatic changes during the Pleistocene. Primarily oceanic forces influence this reef: the Yucatan Current and the large fetch of the waves at this latitude. Five main zones are recognized along the reef profile, based upon scleractinian composition and reef topography. This pattern is similar to that of other areas with a similar geomorphological setting along the Eastern Yucatan reef tract (Jordán-Dahlgren et al., 1981; Jordán-Dahlgren, 1989). A sloping forereef with few high relief features is characteristic of these reefs. Perhaps in part due to this reef morphology, which favors sand accumulation and its resuspension and transport during storms, live scleratinean coral cover on the forereef zone is typically sparse. In contrast, coral cover tends to be dense at the reef crest (Acropora palmata and Millepora complanta) and in the backreef zone (A. palmata and Montastraea annularis). In the forereef zone, the most conspicuous components of the biota are gorgonians, macroalgae, and small hemispherical coral heads of Diploria strigosa, Montastraea cavernosa, and dichocoenia stokesii, among many others. The algae seldom exhibit significant vertical growth, except for seasonally occurring Sargassum spp. and Turbinaria spp. In the few places where high relief reef features exist, the coral community tends to be strongly dominated by large scleractinian colonies, as in any other well developed coral reef. The CARICOMP reef sampling station is located on a typical low-relief forereef. The overall condition of the coral communities of this reef seems good; no extreme situations of bleaching, algal growth, or fish kill have been recorded in the area. At present, the reef is still recovering from the devastating effects of Hurricane Gilbert in 1988. Natural regrowth and recolonization are proceeding at an also variable rate, both between and within the reef zones. Additionally, Diadema antillarum urchins, which almost disappeared after the pan-Caribbean demise and which were further affected by Gilbert in 1988, are gradually becoming abundant again. The reef has undergone, and is recovering from, the effects of a major bleaching event that affected most of the Caribbean Sea during the last months of 1995. No evaluation of its effects has been done. Punta Ballena Reef Coral reefs are scarce around the island and are not associated with seagrasses or mangroves. The paucity of coral reefs on the island may be related to the relatively cold water, the turbidity resulting from the occasionally high productivity of plankton, the proximity of discharge from the Orinoco River, and wind-induced turbulence, as well as normal currents. The definitive causes of the poor representation of hermatypic coral in the region have not been adequately studied. We are unaware of any biological or geological studies in the area of Punta de Mangle, or of any analysis of the marine ecosystems. Wagenaar Hummelinck (1977, 1981) mentioned Punta de Mangle as a site of both marine and land studies but provided no information about the flora and fauna. Goodbody (1984) utilized samples from Punta de Mangle for studies of ascidians. Punta Cahuita Reef The coral reefs are the most studied marine ecosystems on the Caribbean coast of Costa Rica. Of these, the one at the Parque Nacional Cahuita has been studied longer and in greater detail. The reef was described first by Wellington (1974a); since then, high levels of siltation and turbidity have been investigated. Studies have suggested that the high levels of terrigenous sediments are responsible for the siltation and turbidity as well as being the main stressor on the reef (Risk et al., 1980; Cortés, 1981; Cortés and Risk, 1984, 1985; Cortés and Guzmán, 1985a). A study conducted 15 years after these initial observations indicates a continuous deterioration of the coral reef (Cortés, 1994). Descriptions have been published of coral species (Cortés and Guzmán, 1985b; Cortés, 1992b), octocorals (Guzmán and Cortés, 1985), algae (Wellington, 1974b; Soto and Ballentine, 1986), microcrustaceans (Breedy, 1986; Breedy and Murillo, 1995), sponges (Loaiza, 1991), densities of Diadema (Valdez and Villalobos, 1978), and primary productivity (Silva, 1986). Pollution on the reef has been documented by Mata et al. (1987), Rojas (1990), Sandí (1990), and Guzmán and Jiménez (1992). The death of corals and other reef organisms due to high temperatures in 1983 was reported by Cortés et al. (1984), while that resulting from the 1991 earthquake was reported by Cortés et al. (1992). The massive 1983 die-off of Gorgonia was described by Guzmán and Cortés (1984), that of Diadema by Murillo and Cortés (1984). The coral reef is characterized by an outer crest extending for 5 km around Punta Cahuita; the forereef base is at a depth of 15 m. The reef crest is dominated by Millepora complanata Lamarck and coralline algae. A smaller inner crest extends for 500 m around Puerto Vargas; the base of the forereef is at 5-6 m and is built mainly of Agaricia agaricites (Linnaeus) and Porites spp. on the eastern end, and of massive corals in other sections. The reef crest had Acropora palmata (Lamarck), but the species died off in 1983 (Cortés et al., 1984) with little recovery since then. The backreef has Diploria clivosa (Ellis & Solander) and Millepora complanata; the lagoon is mainly rubble, with a few seagrasses and algae. The CARICOMP site is located on the inner crest at the base of the reef at a depth of 5 m. The main coral is Siderastrea siderea (Ellis & Solander), together with Diploria strigosa Dana and a few Montastraea franksi Gregory. Average live coral coverage is 28.8 ± 2.8% (n = 5 x 10-m-long transects). San Andres Reef San Andres is surrounded by a complex reef system on the insular shelf made up of a variety of coral formations: barrier and fringing reefs, patches, and associated lagoons. The windward barrier reef located on the eastern edge of the shelf is compposed of a series of calcareous fossil terraces covered with well developed coral communities (50% live coral) including a wide diversity of hard corals, octocorals, and sponges (geister, 1997). This reef, although not unbroken, runs from the etxreme north to the south end of the island and is 15 km long and 60-80m wide. Spaanse Water Reef Curaçao is completely surrounded by fringing reefs, situated at a distance from the coast ranging from 20 m to 250 m (Van Duyl, 1985). Although the reef profile is variable along the coast, a general pattern can be distinguished. From the shore, mostly consisting of steep cliffs and rubble beaches, a submarine terrace gradually slopes to a - drop-off - at 7-12 m depth (Bak, 1975). Here, the reef slopes steeply at 45°-90°, sometimes interrupted by an inclined terrace at 50-60 m, to a second drop-off at 70-80 m, ending in a sandy plain at 80-90 m (Bak, 1975). Two additional common reef profiles are distinguished by Van Duyl (1985): one profile with a broad terrace, a relatively deep drop-off (15-18 m) and a less steep slope (<30°); the second profile with a narrow terrace, bordering on a subsea cliff wall. At the Caricomp site, the reef corresponds to the first mentioned profile and is bordered by a rubble beach that consists mostly of Acropora fragments. The rubble beach has a high abundance and diversity of intertidal mollusks, indicative of pristine conditions (Nagelkerken and Debrot, 1995). The submarine terrace, where the CARICOMP line transects are situated at a depth of 6-8 m, stretches 75 m seaward from the shore to the drop-off, which is located at a depth of 8 m (see Van Duyl, 1985). The distribution of reef corals in the Netherlands Antilles has been described by Roos (1964, 1971) and Bak (1975, 1977), while Bak (1977) also provided quantitative data on the composition of the coral community in Curaçao. The total number of coral species found in various marine environments in Curaçao is 57, of which 50 species are hermatypic, belonging to 24 genera (Bak, 1975). These numbers indicate that Curaçao belongs to the Caribbean diversity center (Bak, 1977). At the Caricomp reef site, the total number of hermatypic coral species was found to be 28, at a depth of 6-8 m, in an area of 90 m2. Bak (1975) recognized various zones along the vertical reef profile of Curaçao. The shore zone is a high energy environment that is occasionally subject to partial aerial exposure during low tides. In general, typical organisms of this zone are algae, echinoderms, the coral Diploria clivosa, and other encrusting corals (Bak, 1975). At a depth of 1-4 m, the Acropora palmata zone is characterized by the dominance of the coral A. palmata. Encrusting calcareous red algae, such as Porolithon pachydermum, are important stabilizers of the coral rubble in this zone (Bak, 1975). The barren zone, at 3-4.5 m, is largely devoid of coral growth. The substrate consists largely of sand and coral rubble, or coral rock in more exposed areas. The scouring action of the sand and, before the mass mortality, the grazing of the sea urchin Diadema antillarum, largely inhibit larval settlement of benthic organisms (Bak, 1975). Below 4-5 m, coral cover and diversity increase towards the first drop-off, shifting from a sandy bottom with fields of Acropora cervicornis, towards a substrate of coral rock and living coral dominated by Montastraea annularis, Agaricia agaricites, and Madracis mirabilis (Bak, 1975). Coral cover and diversity remain high over the drop-off, but they decrease rapidly below 35-40 m where the influence of sedimentation is high. Here, calcareous red algae become abundant, although the corals Montastraea annularis and Agaricia undata can still be found down to a depth of 80 m (Bak, 1975). The algal zonation on the coral reef at the southwestern coast of the island has been described by Van den Hoek et al. (1975) at Klein Piscadera (near the Carmabi lab) along a depth gradient of 0-20 m. Seven different zones were distinguished, and a profusion of fleshy and filamentous algae were found, averaging 54 species per 25 m2. The highest combined coverage and diversity of fleshy and filamentous algae and of crustose corallines were found in shallow (1-4 m) A. palmata-Porolithon-Millepora reefs, while lowest values were found in the deeper (5-13 m) and rich M. annularis and M. cavernosa coral community (Van den Hoek et al., 1975). It is not known, however, to what extent the algal community at the CARICOMP reef site corresponds to these findings. Few quantitative data are available for the coral reef fish communities of Curaçao. Research on the distribution, abundance, and species diversity of coral reef fishes has been done by Nagelkerken (1974, 1977) and Leloup and Van der Mark (1984), while Briones Sierra (1994) provided quantitative work for the coral reef, mangrove, seagrass, and algal biotopes of Spaanse Water in the vicinity of the CARICOMP seagrass and coral reef sites. The fish community near the latter, at a depth of 8-25 m, is dominated by the four fish species Haemulon chrysargyreum, Acanthurus bahianus, Mulloidichtys martinicus, and Ocyurus chrysurus, accounting for 50% of the total recorded fish abundance (Briones Sierra, 1994). Herbivorous fish of the families Acanthuridae (17%, density 3.9 per 100 m2) and Scaridae (15%, density 3.4 per 100 m2) accounted for about one-third of the total recorded fish abundance, while carnivorous fish accounted for 54%. The coral predator Chaetodon capistratus accounted for 6% (density 1.3 per 100 m2) of total fish abundance. The shallow-water ecosystems of Spaanse Water appear to play an important role as nursery areas and habitats for coral reef fishes (Briones Sierra, 1994). The reefs of Curaçao are heavily overfished as a result of high fishing pressure and the uncontrolled use of spear guns, fish traps, and gill-nets (Van’t Hof et al., 1995). In 1984, Leloup and Van der Mark found groupers (Serranidae) to be smaller and less abundant on the reefs of Curaçao compared to those in Bonaire, and suggested the higher degree of spearfishing in Curaçao as a likely cause. One species, the balloonfish Diodon holocanthus increased in abundance on the reefs of Curaçao as a result of a mass recruitment of juvenile fish in 1994 (Debrot and Nagelkerken, 1997). The coral reefs of Curaçao, including the CARICOMP reef site, have recently been impacted by a number of natural and anthropogenic disturbances. Bak and Nieuwland (1995) found that during the last two decades coral cover and number of coral colonies decreased significantly on the shallow forereef (depths 10 and 20 m) in Curaçao. Species richness also decreased at a depth of 30-40 m, and rare species disappeared. Coastal development activities, such as sewage discharge and artificial beach construction, are likely to have caused the decline of the shallow reef (Bak and Nieuwland, 1995). Curaçao is located outside the hurricane belt. The most recent hurricane passing within 100 nautical miles of the island was Hurricane Joan in 1988 (Meteorological Service, 1990), but its effect on the coral reef was not documented. Tropical storm Brett passed 145 km from Curaçao in 1993 and caused considerable damage to shallow water Acropora palmata and Millepora complanata colonies to a depth of at least 8 m, especially on the exposed eastern side of the southwestern coast of the island (Van Veghel and Hoetjes, 1995). As the CARICOMP reef site is situated in this area, and is located at an exposed promontory, the storm-related damage to the shallow part of this reef was severe as well. Massive coral bleaching has been documented for Curaçao reefs: in 1987 (Williams and Bunkley-Williams, 1990), in 1990 (Meesters and Bak, 1993), and in 1995 (CARICOMP, 1997). The coral Montastraea annularis is normally most heavily affected. The bleaching-related mortality in M. annularis at the CARICOMP reef site during the 1995 bleaching event was found to be much higher in comparison to other more pristine reef areas (Nagelkerken et al., 1997b). As M. annularis is a main reef builder on Curaçao reefs (Bak, 1975), this event may thus have caused a higher than average disturbance of the coral community at the CARICOMP reef compared to other reef areas. Several diseases have had detrimental effects on coral reef organisms of Curaçao reefs in the 1980s and 1990s. In 1980, the corals Acropora palmata and A. cervicornis were affected by white-band disease (Bak and Criens, 1981), and in 1983 the population of the sea urchin Diadema antillarum was reduced by 98-100% by an unknown cause (Bak et al., 1984). The latter resulted in a significant increase in cover of fleshy and filamentous algae in combination with a general decrease in coral, crustose coralline, and/or loose sediment cover (De Ruyter van Steveninck and Bak, 1986). In 1995, widespread mortality was observed in Caribbean sea fans (Gorgonia spp.), and in Curaçao the sea fan Gorgonia ventalina was affected (Nagelkerken et al., 1997a). The effects of the disease appeared to be positively related to water depth; the sea fan community at the CARICOMP reef (depth 5 m) showed 62% of the sea fans to be infected, and the mean percentage of tissue surface injured was 7% (Nagelkerken et al., 1997a). The disease was probably caused by a water-borne pathogen likely to have been distributed by sediment particles (Smith et al., 1996). Finally, according to Bak and Nieuwland (1995) black-band disease in corals is rare in Curaçao. The compound ascidian Trididemnum solidum is a common competitor for space on Curaçao reefs and can easily overgrow corals. Its abundance was first quantified in 1978 by Bak et al. (1981); during a re-survey in 1993, Bak et al. (1996) found that its abundance had increased significantly over 15 years. Eutrophication has been suggested as a possible cause for this increase (Bak and Nieuwland, 1995). So far, T. solidum has not been observed at the CARICOMP reef site, but it is located only 3 km upstream of the nearest reef where the presence of T. solidum has been confirmed (Bak et al., 1996).