The lake ecology of Arctic charr in the Canadian Arctic is poorly defined. This research examined and compared the lake ecology and biological parameters of two differing charr populations (anadromous and landlocked) in Cumberland Sound, Nunavut. Growth differed between the populations, with anadromous charr being larger and having higher overall growth rates. Stomach contents indicated that landlocked charr feed in both fall and winter while anadromous charr did not feed within freshwater. Two discrete size at age classes were detected within the anadromous population, suggesting that significant morphological changes occur following first migration. Three discrete size at age classes were detected within the landlocked population indicative of ontogenetic shifts in diet from invertebrate feeding to piscivory. Littoral habitat was found to be important to all sizes of landlocked charr in both seasons, whereas the littoral habitat was only important for small fish in the winter within the anadromous population.