The overall goal of this research is to understand the role of olfaction in the ecology and life history of fishes. Fish have an acute sense of smell and almost every aspect of their lives is influenced by olfaction (e.g., feeding, reproduction, migration, and predator avoidance). We use an integrative approach, spanning from molecular biology and electrophysiology to field-based behavior. Research focuses on identifying the neuronal pathways involved in recognizing biologically relevant odors and understanding the importance of these odors in the life history and ecology of different fish species. Because the olfactory system plays a critical role at all life stages, manipulation of the olfactory system and olfactory cues may provide simple and effective tools for managing fish populations. Results from the laboratory are used to develop and apply management strategies and culture techniques that will allow us to preserve threatened and endangered populations of fish. For example, a major focus is olfactory imprinting and homing in Pacific salmon. Prior to their seaward migration, juvenile salmon learn (imprint to) specific odors associated with their natal stream and then later use these retained odor memories to guide their homing migration as adults. By understanding the neural mechanisms underlying imprinting, we hope to determine the sensitive periods for imprinting for different salmon species and ultimately develop culture and management practices that will limit the levels of straying in both wild and hatchery fish.