Development of the SCAS (Statistical-Catch-At-Size) Software

We have been developing Statistical-Catch-At-Size (SCAS) software to improve our previous Age-Structured Production Model (ASPM)/Statistical-Catch-At-Age (SCAA). The SCAS is the integrated age-structured stock assessment model based on size, similar to Stock Synthesis (SS3). SCAS is the AD Model Builder implemented application like our ASPM/SCAA software and SS3. SCAS aggregates season, area and spatial component (movement) as ASPM/SCASS, thus it is the simpler and more robust model. This software is driven by the four menus (applications) without any programming, including (a) batch job (grid search), (b) graphical evaluation of the initial results, (c) MCMC and (d) final graphics. Therefore, this software is suitable for the beginners and the non-stock assessment scientists who wish to run the simpler integrated stock assessments easily in a shorter time. This document describes the progress to date on (a)-(b). We plan to complete the remaining (c)-(d) in 2021. For the further development, a diagnosis component (e.g. hindcasting) is planned to be incorporated in the future.