Environmental Monitoring of Coral Bleaching and Disease in the Hawaiian Islands; Belt Transect Surveys and Disease Assessments of Coral Populations in Hawaii, Maui, and Oahu from March 8, 2010 to November 8, 2011

Coral belt transect surveys, focused at quantifying the relative abundance, density, and size-class distribution of the anthozoan and hydrozoan corals, as well as the condition and health state of the coral populations were conducted around the islands of Maui, Hawaii, and Oahu by the NOAA Coral Reef Ecosystem Program and the Hawaii Division of Aquatic Resources (DAR) from March 8, 2010 to November 8, 2011.

The surveys were conducted along two pre-selected transect lines. For coral observations the transect length was 12 m long and the transect width was 1 m wide (0.5 m on each side of the transect line). For coral condition and health observations, the transect length was between 12.5 and 25 m long and the transect width was 1 m, 2 m or 4 m wide (0.5 m, 1.0 m, or 2.0 m on each side of the transect line). The surveyed area was 24 m^2 per site for the coral observations, and ranged from to 25 m^2 to 200 m^2 per site for the disease observations.

Within each transect 1-m segments were surveyed, whereby in each segment all coral colonies whose center fell within 0.5 m of either side of the transect line were identified to the lowest taxonomic level possible (genus or species) and colony size visually estimated and binned by its maximum diameter in one of 7 size classes: 0-5 cm, 5-10 cm, 10-20 cm, 20-40 cm, 40-80 cm, 80-160 cm, or >160 cm.

When a coral colony exhibited signs of disease or compromised health, additional information was separately recorded. Within each of the two transects, all diseased coral colonies whose center fell within 0.5–2 m on each side of each transect line were carefully examined, measured (length and width of the colony in centimeters, when survey time allowed), identified to the lowest taxonomic level possible, and assigned to one of several types of afflictions, including coral and algal diseases, bleaching, infections, infestations, discolorations, predation, pigmentation responses, skeletal growth anomalies, and tissue loss. Severity of the affliction (mild, moderate, marked, severe, acute) was also recorded for a subset of bleaching observations only. Photographic documentation was also captured (archived and documented separately).

Raw survey data includes species presence, colony counts per taxon, colony size (binned sizes for coral observations, colony width and length for a subset of disease observations), affliction observed, and severity of condition (for observations of bleached corals only).