Catch-at-age – Version 4.0: Technical Report

The Norwegian Computing Center and the Institute of Marine Research have over years developed a Bayesian hierarchical model to estimate the catch-at-age of fish. Such a model enables us to obtain estimates of the catch-at-age with appropriate uncertainty. This is considered as essential input in most age structured stock assessment processes. Recent improvements of the model include modelling a haulsize effect in the proportionat-age model. The model is implemented in C with an R interface. This note gives a thorough description of the model and the simulation algorithm corresponding to version 4.0 of the program.