Geomagnetic Orientation Responses of Juvenile Trans-Located Atlantic Salmon (Salmo salar)

Huge numbers of Atlantic salmon have been trans-located for aquaculture farms around the world. There has been a considerable concern regarding escapement and potential interactions with native salmon species. The ability to predict the movement patterns of escaped fish is imperative for risk assessment to native populations. Recent studies suggest that Pacific salmon and trout use the Earth’s magnetic fields to navigate at sea. Exposure to magnetic fields that exist at the periphery of their oceanic foraging range elicit orientation responses that would lead them back to their oceanic foraging grounds. We tested whether juvenile Atlantic salmon that were trans-located from Maine to Oregon for a recreational fishery possessed similar magnetic orientation responses. These fish were exposed to a series of magnetic fields found at the periphery of their native oceanic foraging range, introduced range in the North Pacific, and locations within the southern hemisphere. Our findings, and similar approaches, can be used to give insight into potential distribution patterns of Atlantic salmon in non-native habitats and could potentially serve as a tool for invasion risk assessment.