CRED Rapid Ecological Assessment Line Point Intercept Survey of Benthic Parameter Assessments at Pagan, Marianas in 2011

REA surveys are investigations that provide a high degree of taxonomic resolution for coral, algae, and other macroinvertebrate communities. The majority of REA surveys were conducted along the forereef slopes of individual islands at depths between 10 and 20 m. However, additional habitats including lagoonal-type patch reef and offshore oceanic banks were surveyed when they existed. During REA surveys, biological assessment teams follow highly structured protocols that are repeated at each REA site. Upon arrival at an REA site, divers entered the water and deployed two 25 m transect lines which are shared with coral surveys that gather community structure, diversity, recruitment, and health status data. The sampling effort takes between 60 and 80 min to complete. The selection of REA sites was made in close consultation with local agencies. Factors considered during REA site selection included: (1) ensuring a range of sample sites representative of the benthic and reef fish habitats around each island; (2) selecting a mixture of sites within and outside of marine protected areas; (3) selecting a mixture of both 'impacted' and 'least impacted' sites; (4) selecting some sites adjacent to local villages; and (5) selecting a number of sites that could be compared to and complement previous assessment and monitoring work as well as future coral reef monitoring proposed by local agencies. It is important to note that access to REA sites can be limited by wave exposure, weather conditions, and other environmental factors such as currents, which can affect the ability to re-survey sites between years. Transect placement was guided by: (1) a focus on hard-bottom communities; (2) deploying lines along an isobath to the extent possible at each site, and (3) laying the transect lines into the prevailing current.