Functional diversification of vision in fishes

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My research is designed to advance our understanding of how the light environment affects the structure and function of the visual system in salmonid fishes. Throughout their life history, salmonids move through diverse light environments, from forest-canopied freshwater streams to the open marine environment. Along the way, their eyes are exposed to varying levels of ultraviolet (UV) radiation. Salmonids can detect UV radiation with UV cone photoreceptors and this plays an important role in mediating polarization vision, a sensory capability that guides navigational behavior and migration. However, little is known about the vulnerability of fish and other animals, with UV sensitivity, to potentially harmful UV radiation. Salmonid populations are declining at an alarming rate at a time when levels of UV light in the environment are also changing due to ozone thinning, forestry and mining. Understanding how environmental conditions support healthy visual function is essential to the management of aquatic ecosystems. My research will examine how the light environment influences the development, environmental plasticity and evolution of functionally diverse visual systems in salmonid fishes. I will assess how exposure to UV radiation affects the distribution of UV cones and visual function in the retina. This research will also explore how thyroid hormone regulates developmental changes in the retina in response to UV radiation. Comparing different salmonid species with distinct life history strategies will provide new information about how different patterns of UV sensitivity during development result in diverse visual function and behavior. This research will enhance our understanding of the evolutionary strategies used by salmonids to cope with the broad array of visual environments they encounter during their life history. It will help address important aspects of how organisms function in changing environments in Canada such as those encountered in areas of heavy forestry activity and mining where management of aquatic ecosystems is critical.