Dataset: Benthic community data from surveys of reefs in southwestern Puerto Rico during 2018 and 2020

The surveys were conducted at various shallow depths (3-, 4-, 10-, 15-meters (m)) in the reefs Turrumote 2, Romero, Guilligan Is, Guanica Bay, Cayo Coral, and Punta Guanica. These reefs are located in southwestern Puerto Rico (approx. lat. 17.8849, long. -67.01546, depth 3-15 m).

The methodology used in the field was the line transect method. The length of each line was 10 m.

Five haphazardly placed, 10-m long permanent, linear/band transects were set up in each of at least three depth intervals (0-5, 7-12, and > 15 m) in several localities prior to the arrival of the disease. They were surveyed before the epizootic event started, to estimate initial live coral cover, during the peak of the event to estimate disease prevalence and species impacted, and again after the disease arrested to estimate impact at the population and community levels.

The linear distance (in centimeters (cm)) of each different substrate (live coral colonies, sponges, zoanthids, crustose coralline algae, etc.) under the tape was measured along each ten-meter-long transect. Relative cover (as a percent (%)) for each substrate in each transect was calculated and added up for each transect. The overall and average percent cover for each biological group and substrate was then estimated for each depth and each locality. Variability in live coral cover across depth intervals in each reef and locality, and among localities will be compared before, during, and after the SCTLD epizootic event.

All coral colonies were checked for health status (healthy, SCTLD infected, other diseases, and bleaching) along a band transect (10 x 2 m (20 sqm) marked by the linear tape. Proportions of colonies in each health category will be calculated for each depth, locality, and over time. Variability in the temporal dynamics of SCTLD prevalence for each foundational, susceptible species impacted will be assessed across depth intervals within each locality, across localities, and over time.

Instrumentation:
Besides the individual diving equipment and an underwater camera, no special instruments were needed to collect the live coral cover. A fiberglass graduated 30-m long tape, a PVC pipe (1-m long), a slate, underwater paper, and pencils were the materials used. Additionally, we had HOBO temp loggers (ONSET Corp.) in several localities, which will provide seasonal/annual variability and the number of days/weeks with higher-than-normal water temperatures.