This paper presents two formulations of multiobjective models for the estuary management problem that are based on goal programming procedures. The multiobjectives are selected to be minimum freshwater inflow into bays and estuaries while maximizing the commercial fish harvest for the five fish species. Salinity and harvest are expressed as a function of fresh water inflow in nonlinear regression equations and used as the constraints. A second formulation was developed in which the constraints are expressed in a chance-contrained formulation. The nonlinear multiobjective models developed in this study are applied to the Alavaca-Tres Palacios Estuary in Texas.