The marine ecosystem provides a broad spectrum of services for a wide array of user groups. Such broad use of marine resources often results in use conflicts between ecosystem elements and human interests. To help mitigate these conflicts, the Bayesian Analysis for Spatial Siting (BASS) tool was developed to incorporate both environmental modeled data and subjective stakeholder input while tracking, maintaining and incorporating uncertainty around both data types. The BASS tool is intended to support marine spatial planning decisions where a wide range of potential user groups have interests that conflict regarding siting decisions. The BASS tool incorporates an initial set of twelve (12) Bayesian Belief Network (BBN) models to provide information on ecosystem and economic services such as habitat suitabilities, device suitabilities and usage pressures which include commercial fishing and recreation activities. These models use environmental data as inputs and return suitability values for potential locations in a near real-time on-request basis. BBN methods were selected for this system to take advantage of their intuitive structural components as well as their ability to incorporate and track uncertainty through the modeling process. Stakeholder input is collected in the system using a subset of software from the AccordTM decision support system by Robust Decisions, Inc. This system uses an intuitive two-step data collection method to quantify stakeholder values regarding the decision making process. In the first step, stakeholder participants rank the decision measures, both modeled and subjective, in terms of importance. This ranking scheme allows for weighting later in the process where exploration of the results may require an understanding of stakeholder priorities. The second step uses another component of the AccordTM system called the Belief Map© to collect the stakeholder’s levels of satisfaction and certainty regarding subjective decision measures. Finally, using an online user interface, the BASS tool allows a decision manager to explore the output data for the sites in terms of both the modeled and stakeholder decision measure values. Additionally, the user can view the tool output with the weighting structure of the various stakeholders to better understand the priorities held by different groups. This method allows a decision manager to better understand the character of a decision and guide its progress toward a resolution that best addresses the most important elements of the process.