Diet, gastric evacuation rates and food consumption in a stunted population of Arctic charr, Salvelinus alpinus L., in Takvatn, northern Norway

Diet and food consumption of a stunted population of Arctic charr in Takvatn, northern Norway, was studied throughout the ice-free season. Chironomid pupae dominated the diet in June, July and August, while zooplankton and three-spined sticklebacks dominated in September and October. Estimates of gastric evacuation rates were obtained from laboratory experiments with wild-caught, acclimated charr, and these estimates were used for in situ estimation of food consumption from weights of stomach contents. The daily food consumption was greatest in July, after which it decreased markedly towards autumn. The estimated food intake rates were low, especially in September and October. The food supply appears to be restricted, which is probably the main reason why the charr in Takvaln exhibit stunted growth.