National Coral Reef Monitoring Program: Assessing and Monitoring Cryptic Reef Diversity of Colonizing Marine Invertebrates using Autonomous Reef Monitoring Structures (ARMS) Deployed at Coral Reef Sites across the Mariana Archipelago from 2011 to 2017

This dataset includes species identification data gathered from Autonomous Reef Monitoring Structures (ARMS). These ARMS are used by the NOAA Pacific Islands Fisheries Science Center (PIFSC), Ecosystem Sciences Division (formerly the Coral Reef Ecosystem Division) to assess and monitor cryptic reef diversity in the Marianas as part of the ongoing National Coral Reef Monitoring Program (NCRMP). Developed in collaboration with the Census of Marine Life (CoML) Census of Coral Reef Ecosystems (CReefs), ARMS are designed to mimic the structural complexity of a reef and attract/collect colonizing marine invertebrates. The key innovation of the ARMS method is that biodiversity is sampled over precisely the same surface area in the exact same manner.

This data was gathered at specific reef sites across the Marianas. At these sites, divers entered the water and deployed and/or recovered the ARMS unit. Each unit used to gather this data consists of 23 cm x 23 cm gray, PVC plates stacked in alternating series of 4 open and 4 obstructed layers and attached to a base plate of 35 cm x 45 cm that is affixed to the reef. They are designed to mimic the structural complexity of a reef and attract colonizing invertebrates. Soak times are approximately 3 years. Refer to the data to determine how long a particular unit was underwater as soak times can vary by location.

Upon recovery, each ARMS unit was encapsulated, brought to the surface, disassembled and processed on-board the research ship. Disassembled plates were photographed to document recruited sessile organisms, scraped clean, and preserved in 95% ethanol for future DNA processing. Recruited motile organisms were then sieved into 3 size fractions: 2 mm, 500 um, and 100 um. The 500-um and 100-um fractions were bulked and preserved in 95% ethanol for future DNA processing. The 2-mm fraction was sorted into morphospecies. The DNA sequencing data are not included in this dataset.