Conducting Direct Behavioral Observations on Fish in Subarctic Freshwater Systems: Lessons from Iceland

Territoriality, foraging behavior, and diel activity play key roles in shaping the individual fitness and distribution of stream salmonids. Although these behaviors are likely of similar ecological importance at high versus low latitudes, collecting such data in subarctic and Arctic waters poses several challenges. Short summers reduce the time available for studying behaviors that are primarily of interest during the growing season, and at low water temperatures, fish may reduce their activity levels because of low metabolic demands, rendering prolonged observations difficult. Despite these obstacles, some subarctic freshwater systems provide a unique opportunity for examining the ecological determinants of salmonid behavior. Because of its natural history, volcanic activity, and location, Iceland offers a wide spectrum of freshwater habitats, e.g., in terms of water temperature and productivity. Here, we will present novel findings on the effect of ecological gradients on the behavior and population ecology of salmonids in Icelandic streams, and the challenges and potential solutions to collecting such data in subarctic and Arctic areas.