Release of fishStan version 2.0

Contributed by Dan Stich, posted 1-25-21: Richard Erickson, Jillian Hebert (U.S. Geological Survey Upper Midwest Environmental Sciences Center), and Dan Stich (SUNY Oneonta, NY Chapter AFS) have released fishStan version 2.0 as a USGS Software Release. This is an R package for fitting a collection of hierarchical Bayesian models written in the Stan language, with a focus on fisheries. The R package includes a variety of non-linear growth models such as the von Bertalanffy, Gompertz, and logistic growth models; hierarchical linear regression for length-weight regression and catch curves; and hierarchical logistic regression. There are tutorials in helpfiles explaining how to use the models. Each of these can be used to account for individual or group-based variability. The package assumes existing knowledge of R and hierarchical models but can be substantially easier than writing model code by hand for those new to Stan. You can find out more, including how to install and use the software, here: