Threats to Arctic charr - species interactions and climate change

The overall aims of the project are to determine why Arctic charr (Salvelinus alpinus) is declining in northern lakes and to develop management strategies for their preservation and sustainable use. 

We are investigating whether and why Arctic charr populations are declining in the presence of brown trout (Salmo trutta). Mountain lakes previously sampled are being re-surveyed, and local knowledge from interviews is used to assess changes and how they vary between lake types.

We identify key species interactions and environmental factors that determine the distribution and population characteristics of Arctic charr and brown trout and relate these to ongoing environmental change. Existing databases documenting species occurrences, densities, and population structures are also analyzed. Furthermore, we apply mathematical modeling to examine how competition and predation from brown trout affect charrpopulations in different lake types, and how harvest strategies should be adjusted depending on trout presence.

One of the interesting question that has emerged concerns how Eurasian minnow (Phoxinus phoxinus) affect both Arctic charr and brown trout.

Karin Nilsson is the project manager, and the project also includes former postdoctoral researcher Renee van Dorst, currently a researcher at the Norwegian Institute for Nature Research (NINA). 

The project is performed in collaboration with county boards, Sami villages, local fishermen and other scientists, including Gunnar Öhlund and Kerstin Holmgren at SLU, and Pär Byström at Umeå University.