Coral cover

• zone    DO = DROP-OFF at ~10m depth, LT= Lower Terrace at ~5m depth
• length transect in cm
• rugosity    measure for 3-dimensional complexity reef:  length transect following substrate (cm) / plain length transect (cm)
• Average heigh in cm of coral colonies along transect
• date
• Depth in meters
• start.time   
• end.time  
• latitude
• longitude
• Crustose coralline algal cover (proportion)
• Coral cover (proportion)
• cayno bacterial cover (proportion)
• macroalgal cover (proportion)
• other cover (proportion)
• rubble cover (proportion)
• sand cover (proportion)
• soft coral cover (proportion)
• sponge cover (proportion)
• bare substrate cover (proportion)
• turf cover (proportion)
• Transect to left (L) from starting point and to right (R) from starting point
• MPA=Marine Protected Area, ND=No Diving, NF=No Fishing
• Entry into water, either from boat or from shore
  
   

The Atlantic and Gulf Rapid Reef Assessment (AGRRA) Program champions coral reef conservation and empowers those who protect these diverse ecosystems. We are an international collaboration of scientists, managers, and supporters aimed at improving the regional condition of reefs in the Western Atlantic and Gulf of Mexico. For 20 years, AGRRA has used an innovative regional approach to examine the condition of reef-building corals, algae and fishes and support the conservation of coral reef ecosystems. We curate and distribute data, research and educational materials that support this mission.

The AGRRA program began in 1997 by Dr. Robert N. Ginsburg – the guiding visionary force and mentor behind AGRRA’s efforts for 20 years. Collaborating with numerous colleagues, advisors and students, AGRRA has become a leading advocate for coral reef science and conservation. Dr. Ginsburg has led and supported AGRRA, through his foundation The Ocean Research and Education Foundation (ORE), inspiring new generations of ocean scientists, educators and conservationists.

AGRRA’s initial goals were to provide a standardized assessment of key structural and functional indicators that could be applied to reveal spatial and temporal patterns of regional reef condition. Priority was placed on conducting baseline assessments of remote reefs such as in Cuba, The Bahamas, Panama and Los Roques and on creating educational materials and leading training workshops for in-country partners around the Caribbean.

Since that time, we have collaborated with teams of scientific professionals and partners to fill many gaps, collectively conducted over 2,300 surveys, built one of the largest open-access public databases of coral reef condition, and contributed to numerous peer-reviewed publications and management plans.

A cornerstone of our program has been providing open-access to scientific data collected through our partner network. Over 2,300 surveys and 10,000’s of data scientific metrics of corals, fish, and key invertebrates have been collected throughout reefs in the Caribbean. The AGRRA data portal greatly improves the efficiency, transparency and reliability of data compilation and analysis. AGRRA has become a key source of scientific data used to inform reef policies, legislation, management and conservation.

AGRRA has developed a comprehensive set of visual training tools to help partners learn identification of key reef organisms, their role in reef health, and how to scientifically monitor, track and understand these systems. We strive to promote a learning platform through trainings, exchanges and education materials and to catalyze conservation impact through creative effective communication to wider audiences.

Our goals at AGRRA are to:

• 1. Conduct scientifically sound, comparable regional surveys of the health of coral reefs using a standardized method
• 2. Promote a collaborative learning platform through trainings, exchanges and open-access education materials
• 3. Advance our scientific understanding of coral reefs, analyze data results and provide easy data access with the AGRRA data platform and on-line data entry tools
• 4. Catalyze conservation impact through partnerships and creative effective communication to wider audiences.

To follow the health of the coral reefs of Bonaire and Curacao a number of locations on each island are photographed each year since 1973. At each location a 3 m square at up to 4 different depths is recorded and analysed.

Please contact Wageningen Marine Research for more information.

Bonaire, Netherlands Antilles has one of the healthiest coral reef systems in terms of fish species richness and live coral cover in the Caribbean. Numerous studies investigating the correlation between coral cover and fish diversity in reefs throughout the world have yielded inconsistent results. This study, using data from the REEF Fish Survey Project and a vertical transect method of estimating coral cover, found a significant negative correlation between coral cover and fish diversity on Bonaire. The health of Bonaire’s reef systems fuel the diving industry, which is a major part of the island’s economy. Worldwide fish populations are decreasing due to overfishing and other pressures. In an attempt to monitor the valuable fish populations in Bonaire, data from REEF surveys was used to determine whether fish diversity has decreased over time in Bonaire. Although diversity fluctuated at all sites, overall the fish diversity on Bonaire showed no significant change between 1995 and 2007. However, Bari Reef, which is the most surveyed site in the Caribbean, showed an increase in diversity over time. The number of surveys could explain the increase in diversity due to more intensive sampling than any other site.

This student research was retrieved from Physis: Journal of Marine Science II (Fall 2007)19: 20-26 from CIEE Bonaire.

SCUBA diving on coral reefs is a beneficial economic option for small tropical islands, that can have a lower impact on the environment than alternative options, such as the fishing industry. However, diving can also have a negative impact, when divers physically damage the reefs. The effects of diving on reef fish populations have received little study, though alteration of fish distribution or recruitment in areas with high levels of diving is likely. The purpose of this study was to evaluate the impact of diving on coral and fish communities in Bonaire, Dutch Caribbean. Coral and fish communities at six sites adjacent to a popular dive site were studied. Sites studied included two sites immediately adjacent to the entry where most divers pass, 2 sites (120 m from entry) with intermediate levels of diving and 2 sites (240 m from entry) representing less dived sites. Benthic video transects were conducted at two depths (8-10 m, 15 m), recording coral cover and abundance of Atlantic Gulf Rapid Reef Assessment fish species. Coral cover increased with increasing distance to the north of the site, peaking at 31.2%. Coral cover decreased south of the site, which could be attributed to anthropogenic influences occurring due to southern sites proximity to a main population center. A known relationship between Agaricia spp. and Montastrea annularis complex was observed, with the first increasing at intermediately disturbed site, and the latter decreasing at the same sites. All other factors varied greatly across sites and could not be associated with changes in diver intensity; however they could be associated with anthropogenic pressures. Overall, this study did not show significant diver impact, though it displayed negative trends in relation to anthropogenic factors.

This student research was retrieved from Physis: Journal of Marine Science XI (Fall 2012)19: 21-28 from CIEE Bonaire.

The transition in the Caribbean Sea from coral dominated reefs to algal dominated reefs poses a serious risk to the current existing community. Current research suggests that algal communities will follow a predictable pattern of growth and succession based on the environmental conditions of the community. Depth of the coral head hosting the community and location on the coral head may have a role in succession. This study was conducted on a fringing reef on the leeward side of the island of Bonaire, DC in March of 2014. Algal communities were sampled at two locations on coral heads: just below the livecoral/dead coral interface and between 10 and 30 cm below the first sample. Analysis of genera richness and mass percent of algal divisions were not found to be correlated with depth for all algal divisions. However, richness of Rhodophyta genera was shown to be different between sampling locations on the same coral head and mass percent of Chlorophyta genera was shown to be negatively correlated with distance between sampling locations. The lack of variation found among many of the samples suggests that depth and sampling location on a coral head are largely unimportant in determining the make-up of an algal community, except the aforementioned relationships. Within the framework of creating a predictive model for algal succession, depth and community location on the coral head are components, but more work is needed. The creation of a predictive model will let reef managers forecast future threats and mitigate potential catastrophes.

This student research was retrieved from Physis: Journal of Marine Science XV (Spring 2014)19: 15-20 from CIEE Bonaire.

A greater understanding of coralbased communities must be achieved in order to maximize reef conservation efforts. While a multitude of studies have analyzed coral reef recovery, resilience of reefs, and artificial reefs versus natural reefs, few have dissected the complex ecological networks of coral-based ecosystems during the first few decades of colonization. The following is a quantitative study of invertebrate and fish communities around a series of offshore mooring blocks in Kralendijk, Bonaire (n=18). These blocks were deployed roughly twenty years ago, are the same size, and are exposed to similar physical conditions. It was hypothesized that there would be positive correlations between coral cover and fish species richness, coral cover and fish species diversity, rugosity and fish species richness, and rugosity and fish species diversity. Visual surveys, photo quadrats, and a slightly modified chain intercept transect method were used to assess fish communities, coral cover, and rugosity, respectively. The results supported the hypotheses with significant positive correlations (p<0.05). Likewise, it was found that fire coral cover displayed significant positive correlation with both rugosity (p=0.005) and fish species diversity (p=0.014), whereas brain coral cover did not show a significant correlation with these two variables. Though these outcomes may have been expected based on the findings of previous studies, the manifestation of such ecology in these relatively young mooring blocks is impressive when compared to the same trends in well-established reefs. While this study constituted only a small window of the intricate field of coral reef ecology, the findings offer manageable insight into the dynamics of young artificial structures.

This student research was retrieved from Physis: Journal of Marine Science XVI (Fall 2014)19: 31-37 from CIEE Bonaire.

Stressors causing coral reef degradation are making reefs susceptible to domination by other organisms. One documented phase-shift is increased macroalgal cover of deteriorated reefs. Sponges also have the potential to overtake reefs because of their tolerance for rising temperatures and ocean acidification, ability to outcompete corals for space, and tendency to grow on available substrate created by coral mortality. This study aimed to address gaps in the literature on sponge/coral relationships as well as simultaneously study the interactions between coral and both of its potential competitors. Percentage encrusting sponge cover, percentage algae cover, and encrusting sponge density were compared to percentage live, damaged, and dead coral cover to examine the interactions among coral, sponges, and algae. Sponge/coral interactions were also classified to assess sponge aggressiveness. Data was collected at Yellow Submarine dive site using belt transects and photoquadrats. Although no correlations were significant, most comparisons found that sponges and algae decreased with more live coral cover and increased with more dead coral cover. No significant differences among the abundance of sponge/coral interaction types were found on the reef slope, but there were significant differences present on the reef crest. In both locations, most interactions were not aggressive overgrowth interactions. The relationships among sponges, algae, and coral suggest that both sponges and algae tend to grow on substrate made available by coral death. By examining the interactions of both sponges and algae with coral, comparison of these relationships was possible, potentially prompting future work that also assesses multiple ecologically important interactions.

This student research was retrieved from Physis: Journal of Marine Science XIX (Spring 2016)19: 42-51 from CIEE Bonaire.

To follow the health of the coral reefs of Bonaire and Curacao a number of locations on each island are photographed each year since 1973. At each location a 3 m square at up to 4 different depths is recorded.

Please contact the DCBD administratorfor access to the raw digital photographs.

Unusually warm ocean temperatures surrounding Bonaire during the late summer and fall of 2010 caused 10 to 20 % of corals to bleach (Fig. 1). Bleaching persisted long enough to kill about 10 % of the corals within six months of the event (Steneck, Phillips and Jekielek Chapters 2A – C). That mortality event resulted in the first significant decline in live coral at sites monitored since 1999 (Fig. 2). Live coral declined from a consistent average of 48 % (from 1999 to 2009) to 38 % in 2011 (Steneck Chapter 1). This increase in non-coral substrate increased the area algae can colonize and the area parrotfish must keep cropped short (Mumby and Steneck 2008). For there to be no change in seaweed abundance would require herbivorous fish biomass and population densities to increase, but they have been steadily declining in recent years. This decline in parrotfish continues despite the establishment of no-take areas (called Fish Protection Areas – FPAs) and the recent law that completely bans the harvesting of parrotfish. The other major herbivore throughout the Caribbean is the black spined sea urchin, Diadema antillarum. However, since 2005 Diadema abundance has steadily declined. Damselfishes continue to increase in abundance (except in FPAs) and their aggressive territoriality reduces herbivory where they are present. These declines in herbivory resulted in a marked increase in macroalgae (Steneck Chapter 1). Although patchily distributed, algae on some of Bonaire’s reefs are approaching the Caribbean average (Kramer 2003). All research to date indicates that coral health and recruitment declines directly with increases in algal abundance (e.g., Arnold et al 2010).
On the bright side, predatory fishes are increasing in abundance in general but increasing most strongly in FPAs. Typically, responses to closed areas take 3 - 5 years to begin to manifest themselves. Predators of damselfishes have increased significantly in FPA sites and there, damselfish abundances are trending downward. These trends are the first signs of changes in the FPAs, and they are encouraging.
Overall, Bonaire’s coral reefs today are more seriously threatened with collapse than at any time since monitoring began in 1999.
 
Monitoring Results
The abundance of live coral at the monitoring sites has been remarkably constant since 1999. However, the bleaching related mortality event (Fig. 1) resulted in the first marked decline in live coral.
Seaweed abundance (“macroalgae”) increased sharply in 2011. While the greatest increase in algae occurred at the 18th Palm site where effluent could have increased nutrient levels, most of the other sites showed marked increases in algal abundance (see Steneck Chapter 1). Coralline algae, which has been shown to facilitate coral recruitment, remains at or near unprecedentedly low levels (Fig 2). Herbivory from parrotfishes and the grazing sea urchin Diadema antillarum remains at or near the lowest levels recorded since monitoring began in 1999 (Fig. 3 and see Cleaver Chapter 5). Herbivory from parrotfish is widely thought to be most important (e.g., Steneck and Mumby 2008) but territorial damselfishes can negate parrotfishes’ positive effects by attacking grazing herbivores and preventing them from effectively grazing (Arnold et al 2010). Damselfish abundances have trended upward in recent years (Fig. 3). However, there is a hint of a reversal to this trend in the FPAs (see Arnold Chapter 3). This reversal is consistent with the possibility that areas without fishing have elevated abundances of damselfish predators such as species of groupers and snappers (Randall 1965)  
Predatory fishes including snappers, groupers, barracuda, grunts and others increased in abundance at our monitored sites (Fig. 4 and see DeBey Chapter 6a). Specific predators known to eat damselfishes (see Preziosi Chapter 6b) show variable population densities with only a hint of an increase in 2011.   
Predatory fishes increased in abundance in both biomass (most striking) and population densities (Fig. 5). While biomass of predators in FPA and control sites is identical, the population density of predators is slightly greater at FPA sites
Coral recruitment remained lower than recorded in 2003 and 2005 (Fig. 6). However, the abundance of juvenile corals was higher in 2011 than was quantified in 2009