David Patterson is a research biologist and head of the Environmental Watch program. The program evaluates the impact of different environmental factors on migration success of Pacific salmon in fresh water. A specific example is the evaluation of adverse main stem Fraser River water temperatures and flow on adult sockeye migration success. David provides pre-season and in-season scientific advice to fisheries managers to assist in the prediction of en route loss and pre-spawning mortalities associated with adverse river conditions. The advice is based on a combination of environmental forecasts, ecological modeling and salmon migration research. The biological research seeks to better understand the relationships between freshwater migration conditions and salmon reproductive development, stress response, disease, energy utilization, and homeostasis. Current research projects and interests include: salmon carcass behaviour; reproductive physiology of adult migrators; thermal tolerance and disease progression; interannual variation in energy status of returning sockeye; causes of pre-spawning mortality; post-release stress from fishing; sockeye thermal ecology; climate impacts on migration conditions; smolt condition during freshwater migration; fry out-migration behaviour; and the intergenerational consequences of harsh migration conditions on egg-fry survival and offspring fitness.