PARASITES AS INDICATORS OF INDIVIDUAL FEEDING SPECIALIZATION IN ARCTIC CHARR DURING WINTER IN NORTHERN NORWAY

The relationship between infection with the food-transmitted parasites Diphyllobothrium dendriticum, D. ditremum (Cestoda) and Cystidicola f arionis (Nematoda) and prey selection was studied in individual Arctic charr from Lake Takvatn, northern Norway. There was no correlation be tween parasites transmitted throughout prey organisms from benthic hab itats (amphipods) and pelagic habitats(copepods). A strong relationshi p between infection with a parasite species and the corresponding inte rmediate host from the stomach content of individual charr, indicated an individual feeding specialization. Independent of size, charr speci alized on the intermediate hosts of all three parasite species. Some c harr maintained this specialization on specific prey items throughout the winter period. These parasite species are considered to be useful indicators of past prey selection. (C) 1996 The Fisheries Society of t he British Isles