Benthic Surveys in Fagaʻalu, American Samoa: comprehensive assessment of coral demography (adult and juvenile corals) from belt transect surveys from 2020-01-15 to 2020-01-24 (NCEI Accession 0240418)

The data described here result from benthic coral demographic surveys within belt transects of specified length and width for two life stages (juveniles and adults) in Fagaʻalu, American Samoa in 2020. The data provide information on adult coral colony counts, morphology, size, partial mortality (old and recent dead), presence and causation of disease and other compromised health conditions, including bleaching. Juvenile colony surveys include morphology and size. Taxonomic identification of adult colonies is to the species level and genus level for juveniles.

In 2020, the survey implemented a one-stage stratified random sampling (StRS) design to assess the Fagaʻalu coral reef community. The survey domain encompassed the majority of the mapped area of reef and hard bottom habitats in the 0–30 m depth range. The stratification scheme included cardinal position (i.e., north and south), reef zone (i.e., backreef and forereef) and depth (i.e., shallow: >0–6 m and mid-depth: >6–18 m). Sampling effort allocation was determined based on strata area and sites randomly located within strata. The StRS design effectively reduces estimate variance through stratification using environmental covariates and by sampling more sites rather than more transects per site. Therefore, site-to-site comparisons should proceed with caution.