Measuring Up to the Challenge: Enhancing the Capacity of ARAICoBeH System by Enabling Coral Colony Size Measurement

Abstract

The health of many coral reefs around the globe is being threatened by a variety of local and global stressors, which makes it even more important to assess and monitor them. While the coral cover is one of the easiest and used quantifiers of reef health, the addition of coral colony sizes provides deeper insights into reef recruitment potential, fecundity, and possible environmental conditions for survivability. The use of the ARAICoBeH (A Rapid Assessment Instrument for Coastal Benthic Habitats) System can already provide similar coral cover and composition results as common methods in coral reef monitoring yet are faster and cheaper. The capacity of the ARAICoBeH System was expanded to coral measurements by adding paired lasers, and results were compared with tape measurement and photoquadrat methods. The time and cost to conduct this study were also compared for the three methods. The results illustrate that the ARAICoBeH System with paired laser attachment was able to provide digital reference points that can be used as a scale to accurately measure coral colonies. Colony sizes across different coral lifeforms derived from the system correlated well overall with the two commonly used methods. The colony size distributions from ARAICoBeH more closely resembled the distribution from the photoquadrat data than from the tape measure method. While the varying resolution of images from the ARAICoBeH System took longer to process, the overall time and cost to conduct this study were faster and cheaper, respectively. From these findings, the addition of paired lasers proved to enhance the capability of the ARAICoBeH System as a viable, low-cost, and rapid coral reef assessment method.