The MARSS R package is available on CRAN, GitHub and on the package website.
A first introduction is available at the Quick Start Guide and a more thorough documentation is available at Learning MARSS.
Check out the companion package marssTMB for fast fitting.
Elizabeth E. Holmes, Eric J. Ward, Mark D. Scheuerell and Kellie Wills (2023). MARSS: Multivariate Autoregressive State-Space Modeling. R package version 3.11.8.
Holmes, E. E., M. D. Scheuerell, and E. J. Ward (2023) Analysis of multivariate time-series using the MARSS package. Version 3.11.8. NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Blvd E., Seattle, WA 98112, DOI: 10.5281/zenodo.5781847
Holmes, E. E., Ward, E. J. & Wills, K. (2012) MARSS: Multivariate Autoregressive State-space Models for Analyzing Time-series Data. The R Journal. 4(1):11-19