A brief account of the USAID funded fish stock assessment collaborative Research Support Program is given, with emphasis on its Philippine module, devoted to empirical analyses, modelling and field studies aimed at improved management of exploited multispecies fish stocks.

A method for estimating the instantaneous mortality rate (Z) is presented which was developed from a truncated equation for average length. The model has zero bias at equilibrium, but has no explicit solution for Z so that its solution requires a numerical method.