The Biological Performance Assessment (BioPA) version 3, uses computational fluid dynamics (CFD) and particle trajectory simulations of the hydro-turbine to quantify the exposure of passing fish to a set of known injury mechanisms. By appropriate sampling of the fluid domain, the BioPA assigns exposure probabilities to each mechanism. The exposure probabilities are combined with dose- response data from laboratory stress studies of fish to produce a set of biological BioPA Scores. These metrics provide an objective measure that can be used to compare competing turbines or to refine a new design. A key innovation of the BioPA is incorporation of the concept that the specific route taken by a fish through the turbine domain is a significant factor in the magnitude of stresses that it experiences. Because the turbine environment is very heterogeneous, a fish passing along one route, say, close to the runner hub, may experience quite different conditions than one passing by another, say, near the tip of a blade. The turbine designer will realize the greatest benefits by improving the passage conditions for those routes where more fish tend to pass, rather than focusing on those where the probability of passage is very low. The BioPA version 3 toolset uses CFD software that is already employed by turbine manufacturers. The risk assessment portion runs using Microsoft Excel macros together with laboratory dose-response relationships for different fish species. Most tasks are automated with scripts for efficiency and consistency. The application consists of two components:1. CFD simulation to compute hydraulic variables and particle trajectories2. Scoring Application. A Microsoft Excel application that computes BioPA scores based on statistics from particle trajectories and dose-response relationships.