A synthesis of benthic percent cover data in the Mariana Islands Archipelago covering a period of 22 years (2000-2022) and summarized at three spatial scales (archipelago-, island-, and sub-island-scales) (NCEI Accession 0299811)

The benthic percent cover data described in this record is a result of a synthesizing effort led by the Ecosystem Sciences Division (ESD) to integrate benthic cover data collected during the National Coral Reef Monitoring Program (NCRMP) surveys in the Mariana Islands Archipelago with surveys carried out by jurisdictional partners in Guam and the Commonwealth of the Northern Mariana Islands (CNMI). The raw benthic cover data is derived from already archived NCRMP surveys and private partner data. This project covers a period of over 20 years (2000-2022) and was funded by the CRCP Project #31364, titled "Synthesizing data to assess temporal trends in benthic and reef fish communities across the Mariana archipelago".

Benthic percent cover was estimated for six categories (i.e., calcified, non-calcified, algae, turf, crustose coralline algae, and coral) and produced at three spatial scales: across the archipelago (populated islands versus remote islands), at each populated island (Guam, Rota, Tinian, and Saipan) and some remote islands, and for each downscaled sectors (10 sectors in Guam, four in Rota, four in Tinian, and 9 in Saipan). These estimates were primarily generated from benthic substrate photographs and using the line-point intercept methodology. Benthic substrate photographs are commonly taken along a 30-m transect at every meter at each site and are then analyzed using the web-based annotation tool. The line-point-intercept methodology consists of consecutively placing 25-m line transects (with a usually 5-m inter-transect distance) to determine the benthic composition at predetermined intervals along the transect line.