Data and Methods
The TCRMP collects a range of data from fixed coral reef monitoring locations, including benthic cover, coral health, fish community composition, urchin density, temperature, and ad-hoc assessments of other types of biophysical data. All data is made freely available to the public and shared in good faith; henceforth, please acknowledge use of this data when appropriate by citing the US Virgin Islands Territorial Coral Reef Monitoring program and the website URL or specific annual reports. All data has undergone an intense quality control screening, but if any errors or issues are found please email Nicole Krampitz. Details on methods and other specifics are included in each sub-page, and a metadata tab is included in each downloadable excel sheet (.xlsx).
For more information on the TCRMP project or other types of available data contact Dr. Tyler Smith.
There are several kinds of data available for download.
Benthic Cover
At each site, benthic cover surveys are conducted annually along six 10 m long permanent transects marked with steel or brass rods. Video are recorded along transects with a high definition digital video recorder located approximately 40 cm above the reef contour.
After taping, non-overlapping images from each transect are captured and superimposed with randomly placed dots. Living and non-living substrate are identified and use to calculate percent cover. Coral and some algae are identified to genera or species when possible, and sponges and gorgonians are identified by morphology. The video and images are permanently stored as a historical record of reef condition and are available for more detailed analyses.
Coral Health & Algae Heights
At each site, coral health surveys are conducted annually along six 10 m long permanent transects marked with steel or brass rods. All coral colonies located directly under the transect lines are identified to species, sized along three axes, and assessed for signs of mortality and disease following a modified Atlantic and Gulf Rapid Reef Assessment protocol (Kramer et al. 2005). Partial mortality of coral colonies is broken into two categories: recent partial mortality and old partial mortality.
Diseases are conservatively categorized into recognized Caribbean scleractinian diseases and syndromes that include bleaching, black band disease, dark spots disease, white plague, and yellow band (blotch) disease (following Bruckner 2007). Bleaching is assessed as abnormal paling of the colony, and, when present, the severity of the bleaching (paling or total whitening) and the area of the colony affected are assessed.
Interactions of living coral tissue with algae, sponges, and other potential space competitors is assessed according to the percentage of living tissue affected. In addition, evidence of predation and disturbance (e.g., parrotfish and damselfish bites, fireworms, corallivorous snails) is assessed and, when present, the number of predators is counted.
Algal canopy height is recorded as a measure of suitable space for coral recruitment. Heights of erect algal species are recorded every 50 cm along coral health transects. Where possible algal species are identified to genus or are placed into categories (e.g., turf, filamentous with sediment).
Fish Census
Fish surveys are conducted at all TCRMP sites. Currently, nine replicate belt transects (25 x 4 m) record density of each species* and three 15 minute roving diver surveys record species diversity. Roving diver surveys also capture the presence of rare species, such commercially important large-bodied groupers. Divers also assess the abundance of the black spines sea urchin (Diadema antillarum) along the same fish transects in an area of 25 x 2 m belt transects. *small and cryptic gobies and bennies are not normally captured in the data.
Physical Characteristics
Benthic temperatures are recorded at each site with a HoboTemp™ thermistor data logger (Onset Computer Corporation, Bourne, Massachusetts). Thermistors are affixed in shaded ares of TCRMP transects and set to record at intervals of 15 minutes. Since 2012 thermistor calibration is checked pre- and post-deployment in water baths of known temperature to estimate accuracy. Data is presented here as daily averages, although raw data with higher resolution is available.
Other physical variables that have been measured at a subset of TCRMP sites and times include currents, salinity, dissolved oxygen, photosynthetically active radiation, chlorophyll, turbidity, total suspended solids, and nutrients.
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