The demand for the mass transportation of goods throughout the world is threatening the biodiversity and native habitats of local scale aquatic assemblages. Efforts to preserve and protect marine communities are hampered by the danger of invasive species coming into native harbor community assemblages. In order to manage and conserve these ecosystems, it is necessary that we research and compiled the species in order to gain a better understanding of how legislation and regulations can be used in order to create systems that are sustainable for all species. The goal of this capstone is to examine current and past legislation and regulations as well as look at the species assemblages in San Francisco Bay and Sydney Harbour. We conducted an analysis and evaluation on the current policies of the harbors. To do this, previous data and research were examined; policies and laws were ascertained; and the ongoing impacts of invasive species were determined. Through a literature search we identified all the recorded known species present in each harbor and conducted biodiversity comparisons on the taxa. This paper analyzes and compares a range of factors that may influence policy implementation and legislation in the United States and Australia. Based on reviews of policy and literature, the cross country comparative analysis reveals the challenges and opportunities of the policies in each setting, and the relative strengths and weaknesses of the difference implementation approaches. The paper concludes with recommendations for the United States and Australia in terms of legislative approaches and a do nothing approach