Knowledge of the various descriptors of properties that are encountered in fish immediately after harvest or catch must be known as well as of the changes in properties that take place over time. This information can be gained by performing controlled storage experiments that extend from the time of harvest until spoilage. Freshness, loss of freshness and spoilage can thus be monitored; once the dynamics and the rate of the various changes that occur have been measured, the next step is to try to develop a model. The future aim is to use a model to determine when a sample was harvested or predict the remaining shelf life of an unknown sample. To achieve this aim, it is useful to combine several measurements obtained by different methodologies and correlate the findings with sensory assessments, which are currently the most used method to evaluate fish freshness.