Native to the Gulf of Mexico, Karenia brevis is a toxic dinoflagellate that blooms almost annually off the west coast of Florida. K. brevis blooms are not a new phenomenon on the west Florida shelf, and ships' logs suggest bloom-related events (fish kills) dating back to the 1500s. Coastal regions of Florida have experienced some of the most rapid population growth and development in the United States. Beach clean-ups, tourism-related losses, medical expenses, and lost work days during red tide events can average over a million dollars lost annually. This is a five year, multi-insitutional research program designed to utilize scientific expertise in a collaborative laboratory, field, and modeling program. The study aimed to identify the diverse interannual physical, chemical, and biological conditions that are responsible for K. brevis blooms on the west Florida shelf.