Last spring, biologists Linda Deegan (Marine Biological Laboratory) and Alex Huryn (University of Alabama) began a three-year, National Science Foundation-funded study of arctic graylings (Thymallus arcticus), the only fish found in the Kuparuk River near Toolik Field Station. Grayling serve as food for lake trout, birds, and humans, and the biologists are examining how changing climate affects the migration and life-cycle of grayling populations and, consequently, other facets of the ecosystem like insect populations.
Deegan believes there is an urgency to understanding the relationship between tundra lakes and streams and how they function as a system, given the rapid pace and grand scale of climate change. To that end, this project aims to address 4 questions:
1) How are seasonality, rate and distance of grayling migration affected by climate change?
2) Are the seasonality of life-cycles, life-history and attributes of stream insect populations changing in response to climate change?
3) How does changing seasonality of river discharge interact with insect production to affect availability and transfer of stream production to grayling?
4) What is the effect of climate-driven disruption of the migratory link on the structure and function of winter refugia?
Specifically, the scientists will devote their field work to studying the graylings during downstream migration from Green Cabin Lake at the head of the Kuparuk River. In June and July they will tag fish along a 50 km stretch of Kuparuk. At summer’s end, they will study the graylings as they migrate back upstream for the winter.
This summer, the project was featured on the radio show, Pulse of the Planet, in a series of three field interviews with Heidi Golden, research assistant to Linda Deegan. Follow this link to access the audio reports. —Marcy Davis