Monthly diet composition of: (a) polymorphic Arctic charr from Fjellfrøsvatn from the profundal and littoral habitats and (b) monomorphic Arctic charr from Takvatn caught in the profundal habitat throughout the year (asterisks denotes sampling month with ice). n, number of fish; prey items: L, littoral benthos; Z, zooplankton; I, insect pupae; E, Eurycercus; C, chironomid larvae; B, benthic copepods; P, Pisidium.