Fork lengths were estimated in centimeters by comparing fishes to a ruler attached perpendicular to the end of a 1 m rod. After recording fish data, divers recorded data on habitat features within the sample cylinder including depth, substrate composition, and maximum vertical relief. Estimated percentage composition of various substrates within the sample cylinder was based on the observer's field of view from the center of the sample cylinder. The SST method is simple, well-established, and is being used in many areas around the world. It provides quantitative data for most reef species includes a number of variables that can not be effectively collected using other methods.
Statistical power comes from large sample sizes.
The method reduces bias caused by moving divers and increases the useful bottom time by conserving air. It is best suited for sampling suprabenthic reef species, but is less well suited for cryptic, secretive, and nocturnally active species. It has limited use under conditions of very poor visibility, high surge, and deep depths. A disadvantages is that it provides an index of abundance and biomass but can not easily be used to develop absolute abundance estimates without extensive ground-truth calibration or use of stereo video technology. Fishes Two visually-based methods are used in the Florida Keys to monitor coral reef fishes.