Status of coral communities in American Samoa: a re-survey of long-term monitoring sites in 2002 (NCEI Accession 0001470)

A re-survey of coral communities in the American Samoa Archipelago covering the island of Tutuila and the Manu'a Group of islands (Ofu, Olosega, and Tau), was carried out during March 2002.

All surveyed sites in 2002 were restricted to the 10m deep slope habitat only. The 1995 baseline survey utilized a larger sample size (belt width) within replicate transects, that could not be duplicated in the allocated time for the present survey due to the significant increase in colony densities. The same number of belt transects (5 per site) was used in both surveys for the Manu'a Group sites, but the number of transects per site was reduced to 3 per site on Tutuila. Consequently, sample unit size per site was 50% to 70% of the area sampled in 1995.

Data were analyzed to investigate changes in coral colony size structure, cover, and density, and to interpret community dynamics. The variation in sample effort between surveys and to a less extent, among sites in 2002, meant that pooled analyses were limited, so descriptive and statistical tools were used to interpret community dynamics during the period between the two surveys. Threats and disturbances were also interpreted from features of the coral community dynamics, which included the impacts (and current extent) of coral bleaching as well as crown of thorns starfish infestations.