As part of a wider research project aimed at developing management strategies based on the current toothfish assessment methodology using the Generalised Yield Model (GYM), a Java version of the GYM has been developed. The new version has been developed directly from the specifications kindly provided by Dr Andrew Constable. Some routines have been translated from the GYM FORTRAN code into Java. As such, if sufficiently similar results can be obtained from the JGYM and the current GYM given identical input, then this would be a major step towards a verification of the GYM. This paper, which will be given in the form of a Power Point presentation, will discuss how the JGYM was developed, indicate differences from the GYM where they exist, and compare results from the two programs with identical inputs.
Abstract:
This note describes the most recent additions to Fish Heaven and provides illustrative examples of its application as a tool for evaluating fisheries management systems. As in previous years there have been numerous small changes and additions to the functionality of the program. This note describes the large structural additions which have been made to Fish Heaven and which now allow a very wide range of models to be constructed and explored. The application of Fish Heaven as an evaluation tool is illustrated by some examples of how Catch Per Unit Effort performs as an indicator of abundance under simple stock scenarios.
