Object - oriented ecosystem modelling was introduced in the early of 1990s ( Silvert, 1992 ). From that time on, ecosystem models using object - oriented programming ( OOP ) has earned significant achievements with increasing upgraded information technology. The common purposes of ecosystem modellers are to build a model with flexible structure, which allow continuous modifications on the model content. In last decade, ecosystem modellers have put a large number of efforts to practice the OOP approaches in order to implement a true object - oriented ecosystem model. However, these previous work have not fully take advantage of object - orientation because of misusing more or less this technique. This paper explains the shortcoming of these previous endeavours therewith points out a practical solution that using the methodology of object - oriented software engineering and some relative novel information techniques. A case study SALMO - OO will be presented in this paper to prove Silvert ' s assumption that OOP play an important role on ecosystem modelling approaches. Moreover, the results of SALMO - OO convince that object - oriented ecosystem modelling can be achieved by using object - oriented software engineering associating with a true object - oriented programming language ( Java in this case ). / Thesis (M.Sc.)--School of Earth and Environmental Sciences, 2006.