Invasive aquatic species are considered to be one of the greatest threats to marine biodiversity, coastal economies, and even human health. Ballast water is a primary vector for these bioinvasions. One method of reducing risk of ballast water introductions is mid-ocean exchange of marine ballast water. However, it is widely recognized that this practice has many limitations, including serious ship safety concerns and variable biological effectiveness. International agencies and federal, state and local governments are attempting to tackle the problem by recommending or mandating the installation of ballast water treatment systems. The WFRC is working with others to develop new technologies to detect, prevent, and control aquatic invasive species impacts in Puget Sound and the Pacific Northwest.