Two whitefish morphs have been identified in lakes in northern Norway from a bimodal distribution of gill raker numbers: a sparsely- and a densely-rakered. Habitat choice and feeding ecology of whitefish were studied in five lakes with the two morphs living in sympatry, and in five lakes harbouring only the sparsely-rakered morph. In sympatry, the two whitefish morphs exhibited a strict niche ...