June 20, 2025

New Fieldwork Begins: Studying the Behaviour of Arctic Charr in the Wild!

On June 20, 2025, our team officially launched the fieldwork phase of an exciting new behavioural study on Arctic charr (Salvelinus alpinus). The project is focused on understanding how young salmonids use space, choose their habitat, adopt different foraging modes, and interact with each other in a natural stream environment.


To carry out this research, we installed in-stream enclosures in a local river for a one-month experimental period. Each enclosure is divided into two distinct habitat zones that differ in water flow velocity. This setup allows us to investigate habitat preferences in relation to flow conditions and understand how these preferences may influence territorial behaviour and foraging strategies.

We are applying two complementary behavioural protocols to monitor the fish throughout the study. All individuals have been tagged to allow for individual identification, which is essential for tracking territory location, social interactions, and movement patterns. Our objectives include:

• Determining the location and size of individual territories,
• Observing and recording aggressive interactions to assess social hierarchy,
• Investigating the foraging mode—in particular, where in the water column each fish feeds.

To complement these observations, we are collecting environmental data including water flow rate, depth, and temperature, and we will take drift samples to assess both the availability and composition of invertebrate prey. This will help us understand how food distribution affects space use and competition.

The study is part of a broader research initiative exploring how behavioural traits such as territoriality, foraging mode, and social structure influence space use in animals. In many species, individuals vary greatly in their behavioural strategies, leading to the emergence of social hierarchies with unequal access to key resources like food or shelter. In fish, these dynamics are particularly fluid and can be shaped by external factors such as food availability, environmental conditions, or predation risk.

Our field team is made up of four dedicated members:
– Kelsey, a Master’s student leading the research,
– Jade, a motivated intern supporting data collection,
– and Marie and Franka, experienced field assistants ensuring smooth daily operations on site.
The project is supervised by Stefán, who provides scientific guidance and support throughout the study.
We were also fortunate to have the help of Kelsey’s father, a wildlife biologist, who kindly assisted us in preparing the field site at the start of the experiment.

Together, we aim to shed light on the natural behavioural diversity of Arctic charr juveniles, contributing valuable insights to our understanding of freshwater fish ecology and the role of individual behavioural variation in wild populations.
Stay tuned for updates as the study unfolds!