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Gmacs: a generic size-structured stock assessment model

Gmacs is a generalized modelling framework for developing size-structured stock assessment models. Gmacs is an open source program developed using AD Model Builder (ADMB). Gmacs source files will therefore build on any computer that can run ADMB. ADMB is free, open source, and available for Windows, Linux, MacOS, and Sun/SPARC.

There are four major components to the gmacs project:

• The gmacs assessment model
• The R package gmr
• The code repository (https://github.com/seacode/gmacs)
• Documentation
  • API (http://seacode.github.io/gmacs/)
  • General model description
  • Software manual

This Wiki is designed as a user-manual and developer-guide: it describes how Gmacs can be used to develop size-based stock assessment models and provides details about the source code so that interested users can contribute to development.

The Gmacs framework can make use of a wide range of data sources for both male and female individuals, including survey and fishery indices of abundance and fishery and survey size-composition data. Data must be entered in the form of a text file, model.dat. Control of the model is achieved through the use a separate text file, model.ctl. Examples of data and control files are presented at the end of this guide.