CRED REA Belt Surveys of Coral Population and Disease Assessments at Rota Island, Marianas Archipelago in 2009

To support a long-term NOAA Coral Reef Conservation Program (CRCP) for sustainable management and conservation of coral reef ecosystems, from 5 April - 14 April 2009, belt transect surveys of coral population and diseases quantitative assessments were conducted, as a part of Rapid Ecological Assessments (REA), during the Pacific Reef Assessment and Monitoring Program (RAMP) Cruise HI0902 in the Marianas Archipelago at biennial intervals by the Coral Reef Ecosystem Division (CRED) at the NOAA Pacific Islands Fisheries Science Center (PIFSC). During the cruise, there were 13 surveys in total conducted at REA sites around Rota Island in the Marianas Archipelago. At the specific REA sites, coral biologists along with fish biologists, algal biologists and marine invertebrate zoologist entered the water and conducted a fine-scale (~300 m2) and high degree of taxonomic resolution REA survey to assess and monitor species composition, abundance, percent cover, size distribution, diversity, and general health of fish, corals, macro-invertebrates, and algae in shallow-water (< 35 m) habitats. As a part of REA surveys, the coral belt surveys were focused on quantifying the diversity, abundance, density, and size-class distribution of the anthozoan and hydrozoan corals as well as the condition and health state of the coral reef populations. The surveys were conducted along two consecutively-placed, 25m transect lines. The belt width was dictated at the beginning of each dive by subjective perceived colony density: 1-m width was used in high density areas, while 2-m width was used in low density areas. Within each 25m transect, five 2.5-meter segments were surveyed (beginning at points: 0, 5, 10, 15, and 20 meters), whereby in each segment, all coral colonies whose center fell within 0.5m of either side of the transect line were identified to the lowest taxonomic level possible (genus or species) and two planar size metrics were collected: maximum diameter and diameter perpendicular to the maximum diameter. In addition, the extent of mortality, both recent and old, was estimated for each colony. Observers paid special attention to identifying as best as possible the extent of the former live colony. When a coral colony exhibited signs of disease or compromised health, additional information was recorded including type of affliction (bleaching, skeletal growth anomaly, white syndrome, tissue loss other than white syndrome, trematodiasis, necrosis, other, pigmentation responses, algal overgrowth, and predation), severity of the affliction (mild, moderate, marked, severe, acute), as well as photographic documentation and sometimes tissue samples. Tissue samples were catalogued and fixed in buffered zinc-formalin solution for further histopathological analyses. Raw survey data included species presence and relative abundance, colony counts per taxon, size (width and length), mortality, predation, and health status. A surveyed area was ranging from 10m2 to 25m2 per site.