This report reviews and evaluates methods for estimating fish catch size of major edible species in free-flowing rivers and nearshore marine areas. Based on this effort, a detailed work plan is presented for developing a stepwise regression analysis approach for estimating fish catch size. A literature search was conducted and indicated that the methodology for estimating fish catch size is best developed for marine systems and worst developed for free-flowing rivers. The literature for marine water bodies contains a wealth of regression analysis and correlation efforts (including Box-Jenkins models) that relate one or more physicochemical factors (e.g., temperature, salinity, currents) to fish production or catch size for many species.