LAUSR

While it is known that Dolly Varden Salvelinus malma occupies offshore waters of the Bering and Chukchi seas in Alaska, the general scientific consensus is that this species typically occupies nearshore waters of the Beaufort Sea during its summer feeding season. Because of the importance of offshore waters for many upper trophic level vertebrates in this region, we tested if Dolly Varden occupies this area as well. Therefore, we attached pop-up satellite archival tags (PSATs) to Dolly Varden in the Beaufort Sea. Ten PSATs released from the fish and floated to the surface on pre-programmed dates throughout the summer, and transmitted archived depth and temperature data to satellites, while providing tag end locations. PSATs documented offshore dispersal of up to 69 km from the coast by Dolly Varden during the summer. Tagged fish were surface oriented with mean depths of individuals ranging from 0.1 to 2.2 m (total depth range 0–18.8 m), and experienced an ambient thermal environment of mostly 2–8 °C. The findings of this study highlight the importance of the offshore waters of the Beaufort Sea for Dolly Varden. Such knowledge aids in understanding potential impacts of human activities and environmental change in the Arctic.