Most important food items in the diet of perch from the Mušov reservoir in 1981–1982 (a), 1998 (b) and 2011–2012 (c) based on Costello's (1990) graphical interpretation (as modified by Amundsen et al. (1996)). Note: Mol = Mollusca, Hir = Hirudinea, Zoop = zooplankton, Crus = Crustacea, Het = Heteroptera, Odon = Odonata, Eph = Ephemeroptera, Col = Coleoptera, Trich = Trichoptera, Chir = Chironomidae, Dip = Diptera (except Chironomidae), Cyp = Cyprinid fish, PS = Proterorhinus semilunaris, PF = Perca fluviatilis, Mac = Macrophytes, Det = detritus.