Fishery resources, being renewable, have to be exploited in such a way that reaping of maximum sustainable yield (MSY) is possible without affecting the stocks. For such an effective exploitation, size of stocks is to be determined for obtaining their MSY. But these resources unlike the other living resources, being not in the visual domain for direct evaluation, methods of their assessment need not be the same as used for others.

In this paper an attempt has been made to enumerate different models used for fish stock assessment. Most of the models till date are deterministic. For unit stock assessment these are considered under Macro and Micro-analytic models. Extension of such models for multispecies is also indicated. Stochastic models, though at infant stage are also available and the same too are presented in this paper.