This paper presents four multiobjective models for the estuary management problem, including goal programming, the epsilon constraint method, the surrogate worth tradeoff method and the utility function methods. The multiobjectives are the maximization of commercial fish harvest for five fish species and the minimization of freshwater inflow. Salinity is expressed as a function of freshwater inflow through nonlinear regression equations which are used as constraints. Fish harvests as nonlinear functions of the quantity of freshwater inflow. The multiobjective models are nonlinear programming problems solved by using the GAMS/MINOS programming code. Because of the uncertainty associated with the regression equations for salinity and harvest, the model formulations are extended to chance-constrained formulations. The chance-constrained multiobjective models are solved by using the GRG2 programming code. The multiobjective models are applied to the Lavaca-Tres Palacios Estuary in Texas.