<scp>CoralCT</scp>: A platform for transparent and collaborative analyses of growth parameters in coral skeletal cores

Abstract We present CoralCT, a software application for analysis of annual extension, density, and calcification in coral skeletal cores. CoralCT can be used to analyze computed tomography (CT) scans or X‐ray images of skeletal cores through a process in which observers interact with images of a core to define the locations of annual density bands. The application streamlines this process by organizing the observer‐defined banding patterns and automatically measuring growth parameters. Analyses can be conducted in two or three dimensions, and observers have the option to utilize an automatic band‐detection feature. CoralCT is linked to a server that stores the raw CT and X‐ray image data, as well as output growth rate data for hundreds of cores. Overall, this server‐based system enables broad collaborations on coral core analysis with standardized methods and—crucially—creates a pathway for implementing multiobserver analysis. We assess the method by comparing multiple techniques for measuring annual extension and density, including a corallite‐tracing approach, medical imaging software, two‐dimensional vs. three‐dimensional analyses, and between multiple observers. We recommend that CoralCT be used not only as a measurement tool but also as a platform for data archiving and conducting open, collaborative science.