Summary

Description

Underwater Site 1AP was established at Johnston Atoll by Dr. James Maragos, U.S. Fish Wildlife Service, on June 29, 2000. With a start point meter 0 at latitude 16 46.909N longitude 169 27.757W, a series of metal stakes were pounded into the substrate to delineate a 50meter line that could be relocated and reassessed on future surveys. A fiberglass tape was unrolled along the line marked by the stakes and a series of photographs was taken of the benthos in consecutive 1metersquare 1m x 1m quadrats, using a Nikon RS camera with 35mm colorpositive slide film in an underwater housing mounted atop a 1metersquare 1m x 1m quadrat. The colorpositive slides were later scanned 600dpi using the Epson V750 scanner and software. The overall goal was to acquire data from the photographs and analyze and present quantitative data in a manner to be useful for scientists and refuge management. Each image is labeled with a 3letter location code JOH, date 62900, site number 1AP, and meter interval along the transect line e.g., 56M. The software program SigmaScan Pro 5.0 was used to analyze each image. Analysis was completed by a single observer, Alison Veit. For each photoquadrat, the anthozoan colonies were identified scleractinian genera Acropora, Montipora, Pavona, Pocillopora, Fungia, Leptastrea and the maximum diameter cm of each colony determined. The center of each colony had to fall within the photoquadrat frame in order to be counted for a photoquadrat. If the colony extended beyond one photoquadrat, one diameter was determined and counted in the photoquadrat in which the center of the colony was found. After all the anthozoan colonies in the photoquadrat had been measured, the data were binned into 7 size classes 15 cm, 610 cm, 1120 cm, 2140 cm, 4180 cm, 81160 cm, 160 cm. A visual estimate of percent coral cover in each quadrat was also recorded.