An improved version ofJ.J. Polovina's ECOPATH program for the construction of steady-state multispecies ecosystem models from fisheries data is presented. This new version, called"ECOPATH II,"differs from the original, aside from being more user-friendly, in a number of important features, among others: (1) use of a "generalized inverse" matrix routine allowing the system of linear equations used to estimate model parameters to be over- or slightly underdetermined; (2) estimation of (almost) any set of unknowns and not only of biomasses; (3) explicit consideration of respiratory, egestive and excretory losses (with defaults provided for inputs) and of the detritus pathways; (4) estimation of numerous derived quantities on species group or whole-system basis, such as gross and net efficiencies, trophic levels, food electivity, pathways and cycles involving any groups and "ascendancy" sensuR.E. Ulanowicz. The preliminary version of an empirical multiple regression model for the estimation from easy-to? estimate parameters ofrelative food consumption by fish populations is presented; this model provides reasonable values ofthe input into ecosystem models that were to date mostdifficult to estimate. An application to the coral reef ecosystem ofFrench Frigate Shoals (Hawaii) is presented, along with some suggestions as to how this methodology could be applied to Kuwait waters.